diff --git a/poulpy-core/src/encryption/compressed/gglwe_ksk.rs b/poulpy-core/src/encryption/compressed/gglwe_ksk.rs
index 91f1856..f9549a5 100644
--- a/poulpy-core/src/encryption/compressed/gglwe_ksk.rs
+++ b/poulpy-core/src/encryption/compressed/gglwe_ksk.rs
@@ -25,7 +25,7 @@ impl GLWESwitchingKeyCompressed<Vec<u8>> {
     {
         (GGLWE::encrypt_sk_scratch_space(module, infos) | ScalarZnx::alloc_bytes(module.n(), 1))
             + ScalarZnx::alloc_bytes(module.n(), infos.rank_in().into())
-            + GLWESecretPrepared::alloc_bytes_with(module, infos.rank_out())
+            + GLWESecretPrepared::alloc_bytes(module, infos.rank_out())
     }
 }
 
diff --git a/poulpy-core/src/encryption/gglwe_ksk.rs b/poulpy-core/src/encryption/gglwe_ksk.rs
index ce10a51..5bea8d0 100644
--- a/poulpy-core/src/encryption/gglwe_ksk.rs
+++ b/poulpy-core/src/encryption/gglwe_ksk.rs
@@ -22,7 +22,7 @@ impl GLWESwitchingKey<Vec<u8>> {
     {
         (GGLWE::encrypt_sk_scratch_space(module, infos) | ScalarZnx::alloc_bytes(module.n(), 1))
             + ScalarZnx::alloc_bytes(module.n(), infos.rank_in().into())
-            + GLWESecretPrepared::alloc_bytes(module, &infos.glwe_layout())
+            + GLWESecretPrepared::alloc_bytes_from_infos(module, &infos.glwe_layout())
     }
 
     pub fn encrypt_pk_scratch_space<B: Backend, A>(module: &Module<B>, _infos: &A) -> usize
diff --git a/poulpy-core/src/encryption/gglwe_tsk.rs b/poulpy-core/src/encryption/gglwe_tsk.rs
index 50a646a..330ca0c 100644
--- a/poulpy-core/src/encryption/gglwe_tsk.rs
+++ b/poulpy-core/src/encryption/gglwe_tsk.rs
@@ -23,7 +23,7 @@ impl TensorKey<Vec<u8>> {
         Module<B>:
             SvpPPolAllocBytes + VecZnxNormalizeTmpBytes + VecZnxDftAllocBytes + VecZnxNormalizeTmpBytes + VecZnxBigAllocBytes,
     {
-        GLWESecretPrepared::alloc_bytes_with(module, infos.rank_out())
+        GLWESecretPrepared::alloc_bytes(module, infos.rank_out())
             + module.vec_znx_dft_alloc_bytes(infos.rank_out().into(), 1)
             + module.vec_znx_big_alloc_bytes(1, 1)
             + module.vec_znx_dft_alloc_bytes(1, 1)
diff --git a/poulpy-core/src/encryption/glwe_to_lwe_ksk.rs b/poulpy-core/src/encryption/glwe_to_lwe_ksk.rs
index aee218d..ebbd0f1 100644
--- a/poulpy-core/src/encryption/glwe_to_lwe_ksk.rs
+++ b/poulpy-core/src/encryption/glwe_to_lwe_ksk.rs
@@ -22,7 +22,7 @@ impl GLWEToLWESwitchingKey<Vec<u8>> {
         A: GGLWEInfos,
         Module<B>: SvpPPolAllocBytes + VecZnxNormalizeTmpBytes + VecZnxDftAllocBytes + VecZnxNormalizeTmpBytes,
     {
-        GLWESecretPrepared::alloc_bytes_with(module, infos.rank_in())
+        GLWESecretPrepared::alloc_bytes(module, infos.rank_in())
             + (GLWESwitchingKey::encrypt_sk_scratch_space(module, infos)
                 | GLWESecret::alloc_bytes_with(infos.n(), infos.rank_in()))
     }
diff --git a/poulpy-core/src/encryption/lwe_ksk.rs b/poulpy-core/src/encryption/lwe_ksk.rs
index 4c8b866..4408e6e 100644
--- a/poulpy-core/src/encryption/lwe_ksk.rs
+++ b/poulpy-core/src/encryption/lwe_ksk.rs
@@ -39,7 +39,7 @@ impl LWESwitchingKey<Vec<u8>> {
             "rank_out > 1 is not supported for LWESwitchingKey"
         );
         GLWESecret::alloc_bytes_with(Degree(module.n() as u32), Rank(1))
-            + GLWESecretPrepared::alloc_bytes_with(module, Rank(1))
+            + GLWESecretPrepared::alloc_bytes(module, Rank(1))
             + GLWESwitchingKey::encrypt_sk_scratch_space(module, infos)
     }
 }
diff --git a/poulpy-core/src/layouts/compressed/glwe_ct.rs b/poulpy-core/src/layouts/compressed/glwe_ct.rs
index 576774d..93cb829 100644
--- a/poulpy-core/src/layouts/compressed/glwe_ct.rs
+++ b/poulpy-core/src/layouts/compressed/glwe_ct.rs
@@ -6,9 +6,7 @@ use poulpy_hal::{
     source::Source,
 };
 
-use crate::layouts::{
-    Base2K, BuildError, Degree, GLWECiphertext, GLWEInfos, LWEInfos, Rank, TorusPrecision, compressed::Decompress,
-};
+use crate::layouts::{Base2K, Degree, GLWECiphertext, GLWEInfos, LWEInfos, Rank, TorusPrecision, compressed::Decompress};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use std::fmt;
 
@@ -100,101 +98,6 @@ impl GLWECiphertextCompressed<Vec<u8>> {
     }
 }
 
-pub struct GLWECiphertextCompressedBuilder<D: Data> {
-    data: Option<VecZnx<D>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-    rank: Option<Rank>,
-}
-
-impl<D: Data> GLWECiphertextCompressed<D> {
-    #[inline]
-    pub fn builder() -> GLWECiphertextCompressedBuilder<D> {
-        GLWECiphertextCompressedBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-            rank: None,
-        }
-    }
-}
-
-impl GLWECiphertextCompressedBuilder<Vec<u8>> {
-    #[inline]
-    pub fn layout<A>(mut self, layout: &A) -> Self
-    where
-        A: GLWEInfos,
-    {
-        self.data = Some(VecZnx::alloc(layout.n().into(), 1, layout.size()));
-        self.base2k = Some(layout.base2k());
-        self.k = Some(layout.k());
-        self.rank = Some(layout.rank());
-        self
-    }
-}
-
-impl<D: Data> GLWECiphertextCompressedBuilder<D> {
-    #[inline]
-    pub fn data(mut self, data: VecZnx<D>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-    #[inline]
-    pub fn rank(mut self, rank: Rank) -> Self {
-        self.rank = Some(rank);
-        self
-    }
-
-    pub fn build(self) -> Result<GLWECiphertextCompressed<D>, BuildError> {
-        let data: VecZnx<D> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-        let rank: Rank = self.rank.ok_or(BuildError::MissingK)?;
-
-        if base2k == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k == 0_u32 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if rank == 0_u32 {
-            return Err(BuildError::ZeroRank);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() != 1 {
-            return Err(BuildError::VecZnxColsNotOne);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GLWECiphertextCompressed {
-            data,
-            base2k,
-            k,
-            rank,
-            seed: [0u8; 32],
-        })
-    }
-}
-
 impl<D: DataMut> ReaderFrom for GLWECiphertextCompressed<D> {
     fn read_from<R: std::io::Read>(&mut self, reader: &mut R) -> std::io::Result<()> {
         self.k = TorusPrecision(reader.read_u32::<LittleEndian>()?);
@@ -282,13 +185,13 @@ pub trait GLWECiphertextCompressedToRef {
 
 impl<D: DataRef> GLWECiphertextCompressedToRef for GLWECiphertextCompressed<D> {
     fn to_ref(&self) -> GLWECiphertextCompressed<&[u8]> {
-        GLWECiphertextCompressed::builder()
-            .k(self.k())
-            .base2k(self.base2k())
-            .rank(self.rank())
-            .data(self.data.to_ref())
-            .build()
-            .unwrap()
+        GLWECiphertextCompressed {
+            seed: self.seed.clone(),
+            base2k: self.base2k,
+            k: self.k,
+            rank: self.rank,
+            data: self.data.to_ref(),
+        }
     }
 }
 
@@ -298,12 +201,12 @@ pub trait GLWECiphertextCompressedToMut {
 
 impl<D: DataMut> GLWECiphertextCompressedToMut for GLWECiphertextCompressed<D> {
     fn to_mut(&mut self) -> GLWECiphertextCompressed<&mut [u8]> {
-        GLWECiphertextCompressed::builder()
-            .k(self.k())
-            .base2k(self.base2k())
-            .rank(self.rank())
-            .data(self.data.to_mut())
-            .build()
-            .unwrap()
+        GLWECiphertextCompressed {
+            seed: self.seed.clone(),
+            base2k: self.base2k,
+            k: self.k,
+            rank: self.rank,
+            data: self.data.to_mut(),
+        }
     }
 }
diff --git a/poulpy-core/src/layouts/gglwe_ct.rs b/poulpy-core/src/layouts/gglwe_ct.rs
index 8546499..509e46e 100644
--- a/poulpy-core/src/layouts/gglwe_ct.rs
+++ b/poulpy-core/src/layouts/gglwe_ct.rs
@@ -3,7 +3,7 @@ use poulpy_hal::{
     source::Source,
 };
 
-use crate::layouts::{Base2K, BuildError, Degree, Dnum, Dsize, GLWECiphertext, GLWEInfos, LWEInfos, Rank, TorusPrecision};
+use crate::layouts::{Base2K, Degree, Dnum, Dsize, GLWECiphertext, GLWEInfos, LWEInfos, Rank, TorusPrecision};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 
 use std::fmt;
@@ -132,107 +132,6 @@ impl<D: Data> GGLWEInfos for GGLWE<D> {
     }
 }
 
-pub struct GGLWECiphertextBuilder<D: Data> {
-    data: Option<MatZnx<D>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-    dsize: Option<Dsize>,
-}
-
-impl<D: Data> GGLWE<D> {
-    #[inline]
-    pub fn builder() -> GGLWECiphertextBuilder<D> {
-        GGLWECiphertextBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-            dsize: None,
-        }
-    }
-}
-
-impl GGLWECiphertextBuilder<Vec<u8>> {
-    #[inline]
-    pub fn layout<A>(mut self, infos: &A) -> Self
-    where
-        A: GGLWEInfos,
-    {
-        self.data = Some(MatZnx::alloc(
-            infos.n().into(),
-            infos.dnum().into(),
-            infos.rank_in().into(),
-            (infos.rank_out() + 1).into(),
-            infos.size(),
-        ));
-        self.base2k = Some(infos.base2k());
-        self.k = Some(infos.k());
-        self.dsize = Some(infos.dsize());
-        self
-    }
-}
-
-impl<D: Data> GGLWECiphertextBuilder<D> {
-    #[inline]
-    pub fn data(mut self, data: MatZnx<D>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    #[inline]
-    pub fn dsize(mut self, dsize: Dsize) -> Self {
-        self.dsize = Some(dsize);
-        self
-    }
-
-    pub fn build(self) -> Result<GGLWE<D>, BuildError> {
-        let data: MatZnx<D> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-        let dsize: Dsize = self.dsize.ok_or(BuildError::MissingDigits)?;
-
-        if base2k == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if dsize == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k == 0_u32 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() == 0 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GGLWE {
-            data,
-            base2k,
-            k,
-            dsize,
-        })
-    }
-}
-
 impl<D: DataRef> GGLWE<D> {
     pub fn data(&self) -> &MatZnx<D> {
         &self.data
@@ -272,23 +171,21 @@ impl<D: DataRef> fmt::Display for GGLWE<D> {
 
 impl<D: DataRef> GGLWE<D> {
     pub fn at(&self, row: usize, col: usize) -> GLWECiphertext<&[u8]> {
-        GLWECiphertext::builder()
-            .data(self.data.at(row, col))
-            .base2k(self.base2k())
-            .k(self.k())
-            .build()
-            .unwrap()
+        GLWECiphertext {
+            k: self.k,
+            base2k: self.base2k,
+            data: self.data.at(row, col),
+        }
     }
 }
 
 impl<D: DataMut> GGLWE<D> {
     pub fn at_mut(&mut self, row: usize, col: usize) -> GLWECiphertext<&mut [u8]> {
-        GLWECiphertext::builder()
-            .base2k(self.base2k())
-            .k(self.k())
-            .data(self.data.at_mut(row, col))
-            .build()
-            .unwrap()
+        GLWECiphertext {
+            k: self.k,
+            base2k: self.base2k,
+            data: self.data.at_mut(row, col),
+        }
     }
 }
 
diff --git a/poulpy-core/src/layouts/ggsw_ct.rs b/poulpy-core/src/layouts/ggsw_ct.rs
index 2d8b271..b1fa240 100644
--- a/poulpy-core/src/layouts/ggsw_ct.rs
+++ b/poulpy-core/src/layouts/ggsw_ct.rs
@@ -4,7 +4,7 @@ use poulpy_hal::{
 };
 use std::fmt;
 
-use crate::layouts::{Base2K, BuildError, Degree, Dnum, Dsize, GLWECiphertext, GLWEInfos, LWEInfos, Rank, TorusPrecision};
+use crate::layouts::{Base2K, Degree, Dnum, Dsize, GLWECiphertext, GLWEInfos, LWEInfos, Rank, TorusPrecision};
 
 pub trait GGSWInfos
 where
@@ -105,122 +105,6 @@ impl<D: Data> GGSWInfos for GGSW<D> {
     }
 }
 
-pub struct GGSWCiphertextBuilder<D: Data> {
-    data: Option<MatZnx<D>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-    dsize: Option<Dsize>,
-}
-
-impl<D: Data> GGSW<D> {
-    #[inline]
-    pub fn builder() -> GGSWCiphertextBuilder<D> {
-        GGSWCiphertextBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-            dsize: None,
-        }
-    }
-}
-
-impl GGSWCiphertextBuilder<Vec<u8>> {
-    #[inline]
-    pub fn layout<A>(mut self, infos: &A) -> Self
-    where
-        A: GGSWInfos,
-    {
-        debug_assert!(
-            infos.size() as u32 > infos.dsize().0,
-            "invalid ggsw: ceil(k/base2k): {} <= dsize: {}",
-            infos.size(),
-            infos.dsize()
-        );
-
-        assert!(
-            infos.dnum().0 * infos.dsize().0 <= infos.size() as u32,
-            "invalid ggsw: dnum: {} * dsize:{} > ceil(k/base2k): {}",
-            infos.dnum(),
-            infos.dsize(),
-            infos.size(),
-        );
-
-        self.data = Some(MatZnx::alloc(
-            infos.n().into(),
-            infos.dnum().into(),
-            (infos.rank() + 1).into(),
-            (infos.rank() + 1).into(),
-            infos.size(),
-        ));
-        self.base2k = Some(infos.base2k());
-        self.k = Some(infos.k());
-        self.dsize = Some(infos.dsize());
-        self
-    }
-}
-
-impl<D: Data> GGSWCiphertextBuilder<D> {
-    #[inline]
-    pub fn data(mut self, data: MatZnx<D>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    #[inline]
-    pub fn dsize(mut self, dsize: Dsize) -> Self {
-        self.dsize = Some(dsize);
-        self
-    }
-
-    pub fn build(self) -> Result<GGSW<D>, BuildError> {
-        let data: MatZnx<D> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-        let dsize: Dsize = self.dsize.ok_or(BuildError::MissingDigits)?;
-
-        if base2k == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if dsize == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k == 0_u32 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() == 0 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GGSW {
-            data,
-            base2k,
-            k,
-            dsize,
-        })
-    }
-}
-
 impl<D: DataRef> fmt::Debug for GGSW<D> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "{}", self.data)
@@ -248,23 +132,21 @@ impl<D: DataMut> FillUniform for GGSW<D> {
 
 impl<D: DataRef> GGSW<D> {
     pub fn at(&self, row: usize, col: usize) -> GLWECiphertext<&[u8]> {
-        GLWECiphertext::builder()
-            .data(self.data.at(row, col))
-            .base2k(self.base2k())
-            .k(self.k())
-            .build()
-            .unwrap()
+        GLWECiphertext {
+            k: self.k,
+            base2k: self.base2k,
+            data: self.data.at(row, col),
+        }
     }
 }
 
 impl<D: DataMut> GGSW<D> {
     pub fn at_mut(&mut self, row: usize, col: usize) -> GLWECiphertext<&mut [u8]> {
-        GLWECiphertext::builder()
-            .base2k(self.base2k())
-            .k(self.k())
-            .data(self.data.at_mut(row, col))
-            .build()
-            .unwrap()
+        GLWECiphertext {
+            k: self.k,
+            base2k: self.base2k,
+            data: self.data.at_mut(row, col),
+        }
     }
 }
 
diff --git a/poulpy-core/src/layouts/glwe_ct.rs b/poulpy-core/src/layouts/glwe_ct.rs
index c8cfa4f..7776662 100644
--- a/poulpy-core/src/layouts/glwe_ct.rs
+++ b/poulpy-core/src/layouts/glwe_ct.rs
@@ -5,7 +5,7 @@ use poulpy_hal::{
     source::Source,
 };
 
-use crate::layouts::{Base2K, BuildError, Degree, LWEInfos, Rank, TorusPrecision};
+use crate::layouts::{Base2K, Degree, LWEInfos, Rank, TorusPrecision};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use std::fmt;
 
@@ -86,86 +86,6 @@ impl<D: DataMut> GLWECiphertext<D> {
     }
 }
 
-pub struct GLWECiphertextBuilder<D: Data> {
-    data: Option<VecZnx<D>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-}
-
-impl<D: Data> GLWECiphertext<D> {
-    #[inline]
-    pub fn builder() -> GLWECiphertextBuilder<D> {
-        GLWECiphertextBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-        }
-    }
-}
-
-impl GLWECiphertextBuilder<Vec<u8>> {
-    #[inline]
-    pub fn layout<A>(mut self, layout: &A) -> Self
-    where
-        A: GLWEInfos,
-    {
-        self.data = Some(VecZnx::alloc(
-            layout.n().into(),
-            (layout.rank() + 1).into(),
-            layout.size(),
-        ));
-        self.base2k = Some(layout.base2k());
-        self.k = Some(layout.k());
-        self
-    }
-}
-
-impl<D: Data> GLWECiphertextBuilder<D> {
-    #[inline]
-    pub fn data(mut self, data: VecZnx<D>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    pub fn build(self) -> Result<GLWECiphertext<D>, BuildError> {
-        let data: VecZnx<D> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-
-        if base2k == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k == 0_u32 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() == 0 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GLWECiphertext { data, base2k, k })
-    }
-}
-
 impl<D: Data> LWEInfos for GLWECiphertext<D> {
     fn base2k(&self) -> Base2K {
         self.base2k
diff --git a/poulpy-core/src/layouts/glwe_pk.rs b/poulpy-core/src/layouts/glwe_pk.rs
index 6e947f1..b270b33 100644
--- a/poulpy-core/src/layouts/glwe_pk.rs
+++ b/poulpy-core/src/layouts/glwe_pk.rs
@@ -2,7 +2,7 @@ use poulpy_hal::layouts::{Data, DataMut, DataRef, ReaderFrom, VecZnx, VecZnxToMu
 
 use crate::{
     dist::Distribution,
-    layouts::{Base2K, BuildError, Degree, GLWEInfos, LWEInfos, Rank, TorusPrecision},
+    layouts::{Base2K, Degree, GLWEInfos, LWEInfos, Rank, TorusPrecision},
 };
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 
@@ -22,6 +22,16 @@ pub struct GLWEPublicKeyLayout {
     pub rank: Rank,
 }
 
+pub trait GetDist {
+    fn get_dist(&self) -> Distribution;
+}
+
+impl<D: DataRef> GetDist for GLWEPublicKey<D> {
+    fn get_dist(&self) -> Distribution {
+        self.dist
+    }
+}
+
 impl<D: Data> LWEInfos for GLWEPublicKey<D> {
     fn base2k(&self) -> Base2K {
         self.base2k
@@ -70,91 +80,6 @@ impl GLWEInfos for GLWEPublicKeyLayout {
     }
 }
 
-pub struct GLWEPublicKeyBuilder<D: Data> {
-    data: Option<VecZnx<D>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-}
-
-impl<D: Data> GLWEPublicKey<D> {
-    #[inline]
-    pub fn builder() -> GLWEPublicKeyBuilder<D> {
-        GLWEPublicKeyBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-        }
-    }
-}
-
-impl GLWEPublicKeyBuilder<Vec<u8>> {
-    #[inline]
-    pub fn layout<A>(mut self, layout: &A) -> Self
-    where
-        A: GLWEInfos,
-    {
-        self.data = Some(VecZnx::alloc(
-            layout.n().into(),
-            (layout.rank() + 1).into(),
-            layout.size(),
-        ));
-        self.base2k = Some(layout.base2k());
-        self.k = Some(layout.k());
-        self
-    }
-}
-
-impl<D: Data> GLWEPublicKeyBuilder<D> {
-    #[inline]
-    pub fn data(mut self, data: VecZnx<D>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    pub fn build(self) -> Result<GLWEPublicKey<D>, BuildError> {
-        let data: VecZnx<D> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-
-        if base2k == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k == 0_u32 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() == 0 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GLWEPublicKey {
-            data,
-            base2k,
-            k,
-            dist: Distribution::NONE,
-        })
-    }
-}
-
 impl GLWEPublicKey<Vec<u8>> {
     pub fn alloc<A>(infos: &A) -> Self
     where
diff --git a/poulpy-core/src/layouts/glwe_pt.rs b/poulpy-core/src/layouts/glwe_pt.rs
index c32f229..dfd4b8d 100644
--- a/poulpy-core/src/layouts/glwe_pt.rs
+++ b/poulpy-core/src/layouts/glwe_pt.rs
@@ -3,8 +3,8 @@ use std::fmt;
 use poulpy_hal::layouts::{Data, DataMut, DataRef, VecZnx, VecZnxToMut, VecZnxToRef, ZnxInfos};
 
 use crate::layouts::{
-    Base2K, BuildError, Degree, GLWECiphertext, GLWECiphertextToMut, GLWECiphertextToRef, GLWEInfos, GLWELayoutSet, LWEInfos,
-    Rank, TorusPrecision,
+    Base2K, Degree, GLWECiphertext, GLWECiphertextToMut, GLWECiphertextToRef, GLWEInfos, GLWELayoutSet, LWEInfos, Rank,
+    TorusPrecision,
 };
 
 #[derive(PartialEq, Eq, Copy, Clone, Debug)]
@@ -74,69 +74,6 @@ impl<D: Data> GLWEInfos for GLWEPlaintext<D> {
     }
 }
 
-pub struct GLWEPlaintextBuilder<D: Data> {
-    data: Option<VecZnx<D>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-}
-
-impl<D: Data> GLWEPlaintext<D> {
-    #[inline]
-    pub fn builder() -> GLWEPlaintextBuilder<D> {
-        GLWEPlaintextBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-        }
-    }
-}
-
-impl<D: Data> GLWEPlaintextBuilder<D> {
-    #[inline]
-    pub fn data(mut self, data: VecZnx<D>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    pub fn build(self) -> Result<GLWEPlaintext<D>, BuildError> {
-        let data: VecZnx<D> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-
-        if base2k.0 == 0 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k.0 == 0 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() != 1 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GLWEPlaintext { data, base2k, k })
-    }
-}
-
 impl<D: DataRef> fmt::Display for GLWEPlaintext<D> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
@@ -181,23 +118,21 @@ impl GLWEPlaintext<Vec<u8>> {
 
 impl<D: DataRef> GLWECiphertextToRef for GLWEPlaintext<D> {
     fn to_ref(&self) -> GLWECiphertext<&[u8]> {
-        GLWECiphertext::builder()
-            .data(self.data.to_ref())
-            .k(self.k())
-            .base2k(self.base2k())
-            .build()
-            .unwrap()
+        GLWECiphertext {
+            k: self.k,
+            base2k: self.base2k,
+            data: self.data.to_ref(),
+        }
     }
 }
 
 impl<D: DataMut> GLWECiphertextToMut for GLWEPlaintext<D> {
     fn to_mut(&mut self) -> GLWECiphertext<&mut [u8]> {
-        GLWECiphertext::builder()
-            .k(self.k())
-            .base2k(self.base2k())
-            .data(self.data.to_mut())
-            .build()
-            .unwrap()
+        GLWECiphertext {
+            k: self.k,
+            base2k: self.base2k,
+            data: self.data.to_mut(),
+        }
     }
 }
 
diff --git a/poulpy-core/src/layouts/lwe_ct.rs b/poulpy-core/src/layouts/lwe_ct.rs
index ce5b13a..8c73a4d 100644
--- a/poulpy-core/src/layouts/lwe_ct.rs
+++ b/poulpy-core/src/layouts/lwe_ct.rs
@@ -5,7 +5,7 @@ use poulpy_hal::{
     source::Source,
 };
 
-use crate::layouts::{Base2K, BuildError, Degree, TorusPrecision};
+use crate::layouts::{Base2K, Degree, TorusPrecision};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 
 pub trait LWEInfos {
@@ -153,82 +153,6 @@ impl LWECiphertext<Vec<u8>> {
     }
 }
 
-impl LWECiphertextBuilder<Vec<u8>> {
-    #[inline]
-    pub fn layout<A>(mut self, layout: A) -> Self
-    where
-        A: LWEInfos,
-    {
-        self.data = Some(Zn::alloc((layout.n() + 1).into(), 1, layout.size()));
-        self.base2k = Some(layout.base2k());
-        self.k = Some(layout.k());
-        self
-    }
-}
-
-pub struct LWECiphertextBuilder<D: Data> {
-    data: Option<Zn<D>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-}
-
-impl<D: Data> LWECiphertext<D> {
-    #[inline]
-    pub fn builder() -> LWECiphertextBuilder<D> {
-        LWECiphertextBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-        }
-    }
-}
-
-impl<D: Data> LWECiphertextBuilder<D> {
-    #[inline]
-    pub fn data(mut self, data: Zn<D>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    pub fn build(self) -> Result<LWECiphertext<D>, BuildError> {
-        let data: Zn<D> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-
-        if base2k.0 == 0 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k.0 == 0 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() == 0 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(LWECiphertext { data, base2k, k })
-    }
-}
-
 pub trait LWECiphertextToRef {
     fn to_ref(&self) -> LWECiphertext<&[u8]>;
 }
diff --git a/poulpy-core/src/layouts/mod.rs b/poulpy-core/src/layouts/mod.rs
index 775fb6f..1d8e30d 100644
--- a/poulpy-core/src/layouts/mod.rs
+++ b/poulpy-core/src/layouts/mod.rs
@@ -33,21 +33,16 @@ pub use lwe_pt::*;
 pub use lwe_sk::*;
 pub use lwe_to_glwe_ksk::*;
 
-#[derive(Debug)]
-pub enum BuildError {
-    MissingData,
-    MissingBase2K,
-    MissingK,
-    MissingDigits,
-    ZeroDegree,
-    NonPowerOfTwoDegree,
-    ZeroBase2K,
-    ZeroTorusPrecision,
-    ZeroCols,
-    ZeroLimbs,
-    ZeroRank,
-    ZeroDigits,
-    VecZnxColsNotOne,
+use poulpy_hal::layouts::{Backend, Module};
+
+pub trait GetDegree {
+    fn n(&self) -> Degree;
+}
+
+impl<B: Backend> GetDegree for Module<B> {
+    fn n(&self) -> Degree {
+        Self::n(&self).into()
+    }
 }
 
 /// Newtype over `u32` with arithmetic and comparisons against same type and `u32`.
diff --git a/poulpy-core/src/layouts/prepared/gglwe_atk.rs b/poulpy-core/src/layouts/prepared/gglwe_atk.rs
index 32dd177..e590c21 100644
--- a/poulpy-core/src/layouts/prepared/gglwe_atk.rs
+++ b/poulpy-core/src/layouts/prepared/gglwe_atk.rs
@@ -3,9 +3,8 @@ use poulpy_hal::layouts::{Backend, Data, DataMut, DataRef, Module, Scratch};
 use crate::layouts::{
     AutomorphismKeyToRef, Base2K, Degree, Dnum, Dsize, GGLWEInfos, GLWEInfos, LWEInfos, Rank, TorusPrecision,
     prepared::{
-        GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepareTmpBytes, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedAlloc,
-        GLWESwitchingKeyPreparedAllocBytes, GLWESwitchingKeyPreparedAllocBytesFromInfos, GLWESwitchingKeyPreparedAllocFromInfos,
-        GLWESwitchingKeyPreparedToMut, GLWESwitchingKeyPreparedToRef,
+        GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedAlloc, GLWESwitchingKeyPreparedToMut,
+        GLWESwitchingKeyPreparedToRef,
     },
 };
 
@@ -77,20 +76,9 @@ impl<D: Data, B: Backend> GGLWEInfos for AutomorphismKeyPrepared<D, B> {
     }
 }
 
-pub trait AutomorphismKeyPreparedAlloc<B: Backend> {
-    fn automorphism_key_prepared_alloc(
-        &self,
-        base2k: Base2K,
-        k: TorusPrecision,
-        rank: Rank,
-        dnum: Dnum,
-        dsize: Dsize,
-    ) -> AutomorphismKeyPrepared<Vec<u8>, B>;
-}
-
-impl<B: Backend> AutomorphismKeyPreparedAlloc<B> for Module<B>
+pub trait AutomorphismKeyPreparedAlloc<B: Backend>
 where
-    Module<B>: GLWESwitchingKeyPreparedAlloc<B>,
+    Self: GLWESwitchingKeyPreparedAlloc<B>,
 {
     fn automorphism_key_prepared_alloc(
         &self,
@@ -105,18 +93,7 @@ where
             p: 0,
         }
     }
-}
 
-pub trait AutomorphismKeyPreparedAllocFromInfos<B: Backend> {
-    fn automorphism_key_prepared_alloc_from_infos<A>(&self, infos: &A) -> AutomorphismKeyPrepared<Vec<u8>, B>
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> AutomorphismKeyPreparedAllocFromInfos<B> for Module<B>
-where
-    Module<B>: GLWESwitchingKeyPreparedAllocFromInfos<B>,
-{
     fn automorphism_key_prepared_alloc_from_infos<A>(&self, infos: &A) -> AutomorphismKeyPrepared<Vec<u8>, B>
     where
         A: GGLWEInfos,
@@ -126,28 +103,15 @@ where
             infos.rank_out(),
             "rank_in != rank_out is not supported for AutomorphismKeyPrepared"
         );
-        AutomorphismKeyPrepared {
-            key: self.glwe_switching_key_prepared_alloc_from_infos(infos),
-            p: 0,
-        }
+        self.automorphism_key_prepared_alloc(
+            infos.base2k(),
+            infos.k(),
+            infos.rank(),
+            infos.dnum(),
+            infos.dsize(),
+        )
     }
-}
 
-pub trait AutomorphismKeyPreparedAllocBytes<B: Backend> {
-    fn automorphism_key_prepared_alloc_bytes(
-        &self,
-        base2k: Base2K,
-        k: TorusPrecision,
-        rank: Rank,
-        dnum: Dnum,
-        dsize: Dsize,
-    ) -> usize;
-}
-
-impl<B: Backend> AutomorphismKeyPreparedAllocBytes<B> for Module<B>
-where
-    Module<B>: GLWESwitchingKeyPreparedAllocBytes<B>,
-{
     fn automorphism_key_prepared_alloc_bytes(
         &self,
         base2k: Base2K,
@@ -158,18 +122,7 @@ where
     ) -> usize {
         self.glwe_switching_key_prepared_alloc_bytes(base2k, k, rank, rank, dnum, dsize)
     }
-}
 
-pub trait AutomorphismKeyPreparedAllocBytesFromInfos<B: Backend> {
-    fn automorphism_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> AutomorphismKeyPreparedAllocBytesFromInfos<B> for Module<B>
-where
-    Module<B>: GLWESwitchingKeyPreparedAllocBytesFromInfos<B>,
-{
     fn automorphism_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
     where
         A: GGLWEInfos,
@@ -179,15 +132,23 @@ where
             infos.rank_out(),
             "rank_in != rank_out is not supported for GGLWEAutomorphismKeyPrepared"
         );
-        self.glwe_switching_key_prepared_alloc_bytes_from_infos(infos)
+        self.automorphism_key_prepared_alloc_bytes(
+            infos.base2k(),
+            infos.k(),
+            infos.rank(),
+            infos.dnum(),
+            infos.dsize(),
+        )
     }
 }
 
+impl<B: Backend> AutomorphismKeyPreparedAlloc<B> for Module<B> where Module<B>: GLWESwitchingKeyPreparedAlloc<B> {}
+
 impl<B: Backend> AutomorphismKeyPrepared<Vec<u8>, B> {
     pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
     where
         A: GGLWEInfos,
-        Module<B>: AutomorphismKeyPreparedAllocFromInfos<B>,
+        Module<B>: AutomorphismKeyPreparedAlloc<B>,
     {
         module.automorphism_key_prepared_alloc_from_infos(infos)
     }
@@ -202,28 +163,22 @@ impl<B: Backend> AutomorphismKeyPrepared<Vec<u8>, B> {
     pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
     where
         A: GGLWEInfos,
-        Module<B>: AutomorphismKeyPreparedAllocBytesFromInfos<B>,
+        Module<B>: AutomorphismKeyPreparedAlloc<B>,
     {
         module.automorphism_key_prepared_alloc_bytes_from_infos(infos)
     }
 
     pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank: Rank, dnum: Dnum, dsize: Dsize) -> usize
     where
-        Module<B>: AutomorphismKeyPreparedAllocBytes<B>,
+        Module<B>: AutomorphismKeyPreparedAlloc<B>,
     {
         module.automorphism_key_prepared_alloc_bytes(base2k, k, rank, dnum, dsize)
     }
 }
 
-pub trait AutomorphismKeyPrepareTmpBytes {
-    fn automorphism_key_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> AutomorphismKeyPrepareTmpBytes for Module<B>
+pub trait AutomorphismKeyPrepare<B: Backend>
 where
-    Module<B>: GLWESwitchingKeyPrepareTmpBytes,
+    Self: GLWESwitchingKeyPrepare<B>,
 {
     fn automorphism_key_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
     where
@@ -231,28 +186,7 @@ where
     {
         self.glwe_switching_key_prepare_tmp_bytes(infos)
     }
-}
 
-impl<D: DataRef, B: Backend> AutomorphismKeyPrepared<D, B> {
-    pub fn prepare_tmp_bytes(&self, module: &Module<B>) -> usize
-    where
-        Module<B>: AutomorphismKeyPrepareTmpBytes,
-    {
-        module.automorphism_key_prepare_tmp_bytes(self)
-    }
-}
-
-pub trait AutomorphismKeyPrepare<B: Backend> {
-    fn automorphism_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
-    where
-        R: AutomorphismKeyPreparedToMut<B> + SetAutomorphismGaloisElement,
-        O: AutomorphismKeyToRef + GetAutomorphismGaloisElement;
-}
-
-impl<B: Backend> AutomorphismKeyPrepare<B> for Module<B>
-where
-    Module<B>: GLWESwitchingKeyPrepare<B>,
-{
     fn automorphism_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
     where
         R: AutomorphismKeyPreparedToMut<B> + SetAutomorphismGaloisElement,
@@ -263,6 +197,27 @@ where
     }
 }
 
+impl<B: Backend> AutomorphismKeyPrepare<B> for Module<B> where Module<B>: GLWESwitchingKeyPrepare<B> {}
+
+impl<B: Backend> AutomorphismKeyPrepared<Vec<u8>, B> {
+    pub fn prepare_tmp_bytes(&self, module: &Module<B>) -> usize
+    where
+        Module<B>: GLWESwitchingKeyPrepare<B>,
+    {
+        module.automorphism_key_prepare_tmp_bytes(self)
+    }
+}
+
+impl<D: DataMut, B: Backend> AutomorphismKeyPrepared<D, B> {
+    pub fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &mut Scratch<B>)
+    where
+        O: AutomorphismKeyToRef + GetAutomorphismGaloisElement,
+        Module<B>: AutomorphismKeyPrepare<B>,
+    {
+        module.automorphism_key_prepare(self, other, scratch);
+    }
+}
+
 pub trait AutomorphismKeyPreparedToMut<B: Backend> {
     fn to_mut(&mut self) -> AutomorphismKeyPrepared<&mut [u8], B>;
 }
diff --git a/poulpy-core/src/layouts/prepared/gglwe_ct.rs b/poulpy-core/src/layouts/prepared/gglwe_ct.rs
index 077ad7c..6060e80 100644
--- a/poulpy-core/src/layouts/prepared/gglwe_ct.rs
+++ b/poulpy-core/src/layouts/prepared/gglwe_ct.rs
@@ -1,11 +1,10 @@
 use poulpy_hal::{
     api::{VmpPMatAlloc, VmpPMatAllocBytes, VmpPrepare, VmpPrepareTmpBytes},
     layouts::{Backend, Data, DataMut, DataRef, Module, Scratch, VmpPMat, VmpPMatToMut, VmpPMatToRef, ZnxInfos},
-    oep::VmpPMatAllocBytesImpl,
 };
 
 use crate::layouts::{
-    Base2K, BuildError, Degree, Dnum, Dsize, GGLWE, GGLWEInfos, GGLWEToRef, GLWEInfos, LWEInfos, Rank, TorusPrecision,
+    Base2K, Degree, Dnum, Dsize, GGLWE, GGLWEInfos, GGLWEToRef, GLWEInfos, GetDegree, LWEInfos, Rank, TorusPrecision,
 };
 
 #[derive(PartialEq, Eq)]
@@ -58,123 +57,9 @@ impl<D: Data, B: Backend> GGLWEInfos for GGLWEPrepared<D, B> {
     }
 }
 
-pub struct GGLWEPreparedBuilder<D: Data, B: Backend> {
-    data: Option<VmpPMat<D, B>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-    dsize: Option<Dsize>,
-}
-
-impl<D: Data, B: Backend> GGLWEPrepared<D, B> {
-    #[inline]
-    pub fn builder() -> GGLWEPreparedBuilder<D, B> {
-        GGLWEPreparedBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-            dsize: None,
-        }
-    }
-}
-
-impl<B: Backend> GGLWEPreparedBuilder<Vec<u8>, B> {
-    #[inline]
-    pub fn layout<A>(mut self, infos: &A) -> Self
-    where
-        A: GGLWEInfos,
-        B: VmpPMatAllocBytesImpl<B>,
-    {
-        self.data = Some(VmpPMat::alloc(
-            infos.n().into(),
-            infos.dnum().into(),
-            infos.rank_in().into(),
-            (infos.rank_out() + 1).into(),
-            infos.size(),
-        ));
-        self.base2k = Some(infos.base2k());
-        self.k = Some(infos.k());
-        self.dsize = Some(infos.dsize());
-        self
-    }
-}
-
-impl<D: Data, B: Backend> GGLWEPreparedBuilder<D, B> {
-    #[inline]
-    pub fn data(mut self, data: VmpPMat<D, B>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    #[inline]
-    pub fn dsize(mut self, dsize: Dsize) -> Self {
-        self.dsize = Some(dsize);
-        self
-    }
-
-    pub fn build(self) -> Result<GGLWEPrepared<D, B>, BuildError> {
-        let data: VmpPMat<D, B> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-        let dsize: Dsize = self.dsize.ok_or(BuildError::MissingDigits)?;
-
-        if base2k == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if dsize == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k == 0_u32 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() == 0 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GGLWEPrepared {
-            data,
-            base2k,
-            k,
-            dsize,
-        })
-    }
-}
-
-pub trait GGLWEPreparedAlloc<B: Backend> {
-    fn gglwe_prepared_alloc(
-        &self,
-        base2k: Base2K,
-        k: TorusPrecision,
-        rank_in: Rank,
-        rank_out: Rank,
-        dnum: Dnum,
-        dsize: Dsize,
-    ) -> GGLWEPrepared<Vec<u8>, B>;
-}
-
-impl<B: Backend> GGLWEPreparedAlloc<B> for Module<B>
+pub trait GGLWEPreparedAlloc<B: Backend>
 where
-    Module<B>: VmpPMatAlloc<B>,
+    Self: GetDegree + VmpPMatAlloc<B> + VmpPMatAllocBytes,
 {
     fn gglwe_prepared_alloc(
         &self,
@@ -206,23 +91,12 @@ where
             dsize,
         }
     }
-}
 
-pub trait GGLWEPreparedAllocFromInfos<B: Backend> {
-    fn gglwe_prepared_alloc_from_infos<A>(&self, infos: &A) -> GGLWEPrepared<Vec<u8>, B>
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> GGLWEPreparedAllocFromInfos<B> for Module<B>
-where
-    Module<B>: GGLWEPreparedAlloc<B>,
-{
     fn gglwe_prepared_alloc_from_infos<A>(&self, infos: &A) -> GGLWEPrepared<Vec<u8>, B>
     where
         A: GGLWEInfos,
     {
-        assert_eq!(self.n() as u32, infos.n(), "module.n() != infos.n()");
+        assert_eq!(self.n(), infos.n());
         self.gglwe_prepared_alloc(
             infos.base2k(),
             infos.k(),
@@ -232,24 +106,7 @@ where
             infos.dsize(),
         )
     }
-}
 
-pub trait GGLWEPreparedAllocBytes<B: Backend> {
-    fn gglwe_prepared_alloc_bytes(
-        &self,
-        base2k: Base2K,
-        k: TorusPrecision,
-        rank_in: Rank,
-        rank_out: Rank,
-        dnum: Dnum,
-        dsize: Dsize,
-    ) -> usize;
-}
-
-impl<B: Backend> GGLWEPreparedAllocBytes<B> for Module<B>
-where
-    Module<B>: VmpPMatAllocBytes,
-{
     fn gglwe_prepared_alloc_bytes(
         &self,
         base2k: Base2K,
@@ -275,23 +132,12 @@ where
 
         self.vmp_pmat_alloc_bytes(dnum.into(), rank_in.into(), (rank_out + 1).into(), size)
     }
-}
 
-pub trait GGLWEPreparedAllocBytesFromInfos<B: Backend> {
-    fn gglwe_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> GGLWEPreparedAllocBytesFromInfos<B> for Module<B>
-where
-    Module<B>: GGLWEPreparedAllocBytes<B>,
-{
     fn gglwe_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
     where
         A: GGLWEInfos,
     {
-        assert_eq!(self.n() as u32, infos.n(), "module.n() != infos.n()");
+        assert_eq!(self.n(), infos.n());
         self.gglwe_prepared_alloc_bytes(
             infos.base2k(),
             infos.k(),
@@ -303,11 +149,15 @@ where
     }
 }
 
-impl<B: Backend> GGLWEPrepared<Vec<u8>, B> {
+impl<B: Backend> GGLWEPreparedAlloc<B> for Module<B> where Module<B>: GetDegree + VmpPMatAlloc<B> + VmpPMatAllocBytes {}
+
+impl<B: Backend> GGLWEPrepared<Vec<u8>, B>
+where
+    Module<B>: GGLWEPreparedAlloc<B>,
+{
     pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
     where
         A: GGLWEInfos,
-        Module<B>: GGLWEPreparedAllocFromInfos<B>,
     {
         module.gglwe_prepared_alloc_from_infos(infos)
     }
@@ -320,17 +170,13 @@ impl<B: Backend> GGLWEPrepared<Vec<u8>, B> {
         rank_out: Rank,
         dnum: Dnum,
         dsize: Dsize,
-    ) -> Self
-    where
-        Module<B>: GGLWEPreparedAlloc<B>,
-    {
+    ) -> Self {
         module.gglwe_prepared_alloc(base2k, k, rank_in, rank_out, dnum, dsize)
     }
 
     pub fn alloc_bytes_from_infos<A>(module: &Module<B>, infos: &A) -> usize
     where
         A: GGLWEInfos,
-        Module<B>: GGLWEPreparedAllocBytesFromInfos<B>,
     {
         module.gglwe_prepared_alloc_bytes_from_infos(infos)
     }
@@ -343,23 +189,14 @@ impl<B: Backend> GGLWEPrepared<Vec<u8>, B> {
         rank_out: Rank,
         dnum: Dnum,
         dsize: Dsize,
-    ) -> usize
-    where
-        Module<B>: GGLWEPreparedAllocBytes<B>,
-    {
+    ) -> usize {
         module.gglwe_prepared_alloc_bytes(base2k, k, rank_in, rank_out, dnum, dsize)
     }
 }
 
-pub trait GGLWEPrepareTmpBytes {
-    fn gglwe_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> GGLWEPrepareTmpBytes for Module<B>
+pub trait GGLWEPrepare<B: Backend>
 where
-    Module<B>: VmpPrepareTmpBytes,
+    Self: GetDegree + VmpPrepareTmpBytes + VmpPrepare<B>,
 {
     fn gglwe_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
     where
@@ -372,28 +209,7 @@ where
             infos.size(),
         )
     }
-}
 
-impl<B: Backend> GGLWEPrepared<Vec<u8>, B> {
-    pub fn prepare_tmp_bytes(&self, module: &Module<B>) -> usize
-    where
-        Module<B>: GGLWEPrepareTmpBytes,
-    {
-        module.gglwe_prepare_tmp_bytes(self)
-    }
-}
-
-pub trait GGLWEPrepare<B: Backend> {
-    fn gglwe_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
-    where
-        R: GGLWEPreparedToMut<B>,
-        O: GGLWEToRef;
-}
-
-impl<B: Backend> GGLWEPrepare<B> for Module<B>
-where
-    Module<B>: VmpPrepare<B>,
-{
     fn gglwe_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
     where
         R: GGLWEPreparedToMut<B>,
@@ -402,8 +218,8 @@ where
         let mut res: GGLWEPrepared<&mut [u8], B> = res.to_mut();
         let other: GGLWE<&[u8]> = other.to_ref();
 
-        assert_eq!(res.n(), self.n() as u32);
-        assert_eq!(other.n(), self.n() as u32);
+        assert_eq!(res.n(), self.n());
+        assert_eq!(other.n(), self.n());
         assert_eq!(res.base2k, other.base2k);
         assert_eq!(res.k, other.k);
         assert_eq!(res.dsize, other.dsize);
@@ -412,11 +228,13 @@ where
     }
 }
 
+impl<B: Backend> GGLWEPrepare<B> for Module<B> where Self: GetDegree + VmpPrepareTmpBytes + VmpPrepare<B> {}
+
 impl<D: DataMut, B: Backend> GGLWEPrepared<D, B>
 where
     Module<B>: GGLWEPrepare<B>,
 {
-    fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &mut Scratch<B>)
+    pub fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &mut Scratch<B>)
     where
         O: GGLWEToRef,
     {
@@ -424,6 +242,15 @@ where
     }
 }
 
+impl<B: Backend> GGLWEPrepared<Vec<u8>, B> {
+    pub fn prepare_tmp_bytes(&self, module: &Module<B>) -> usize
+    where
+        Module<B>: GGLWEPrepare<B>,
+    {
+        module.gglwe_prepare_tmp_bytes(self)
+    }
+}
+
 pub trait GGLWEPreparedToMut<B: Backend> {
     fn to_mut(&mut self) -> GGLWEPrepared<&mut [u8], B>;
 }
diff --git a/poulpy-core/src/layouts/prepared/gglwe_ksk.rs b/poulpy-core/src/layouts/prepared/gglwe_ksk.rs
index 7f3aa97..6d1e443 100644
--- a/poulpy-core/src/layouts/prepared/gglwe_ksk.rs
+++ b/poulpy-core/src/layouts/prepared/gglwe_ksk.rs
@@ -3,10 +3,7 @@ use poulpy_hal::layouts::{Backend, Data, DataMut, DataRef, Module, Scratch};
 use crate::layouts::{
     Base2K, Degree, Dnum, Dsize, GGLWEInfos, GLWEInfos, GLWESwitchingKeySetMetaData, GLWESwitchingKeyToRef,
     GLWESwtichingKeyGetMetaData, LWEInfos, Rank, TorusPrecision,
-    prepared::{
-        GGLWEPrepare, GGLWEPrepareTmpBytes, GGLWEPrepared, GGLWEPreparedAlloc, GGLWEPreparedAllocBytes,
-        GGLWEPreparedAllocBytesFromInfos, GGLWEPreparedAllocFromInfos, GGLWEPreparedToMut, GGLWEPreparedToRef,
-    },
+    prepared::{GGLWEPrepare, GGLWEPrepared, GGLWEPreparedAlloc, GGLWEPreparedToMut, GGLWEPreparedToRef},
 };
 
 #[derive(PartialEq, Eq)]
@@ -78,21 +75,9 @@ impl<D: Data, B: Backend> GGLWEInfos for GLWESwitchingKeyPrepared<D, B> {
     }
 }
 
-pub trait GLWESwitchingKeyPreparedAlloc<B: Backend> {
-    fn glwe_switching_key_prepared_alloc(
-        &self,
-        base2k: Base2K,
-        k: TorusPrecision,
-        rank_in: Rank,
-        rank_out: Rank,
-        dnum: Dnum,
-        dsize: Dsize,
-    ) -> GLWESwitchingKeyPrepared<Vec<u8>, B>;
-}
-
-impl<B: Backend> GLWESwitchingKeyPreparedAlloc<B> for Module<B>
+pub trait GLWESwitchingKeyPreparedAlloc<B: Backend>
 where
-    Module<B>: GGLWEPreparedAlloc<B>,
+    Self: GGLWEPreparedAlloc<B>,
 {
     fn glwe_switching_key_prepared_alloc(
         &self,
@@ -109,46 +94,21 @@ where
             sk_out_n: 0,
         }
     }
-}
 
-pub trait GLWESwitchingKeyPreparedAllocFromInfos<B: Backend> {
-    fn glwe_switching_key_prepared_alloc_from_infos<A>(&self, infos: &A) -> GLWESwitchingKeyPrepared<Vec<u8>, B>
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> GLWESwitchingKeyPreparedAllocFromInfos<B> for Module<B>
-where
-    Module<B>: GGLWEPreparedAllocFromInfos<B>,
-{
     fn glwe_switching_key_prepared_alloc_from_infos<A>(&self, infos: &A) -> GLWESwitchingKeyPrepared<Vec<u8>, B>
     where
         A: GGLWEInfos,
     {
-        GLWESwitchingKeyPrepared::<Vec<u8>, B> {
-            key: self.gglwe_prepared_alloc_from_infos(infos),
-            sk_in_n: 0,
-            sk_out_n: 0,
-        }
+        self.glwe_switching_key_prepared_alloc(
+            infos.base2k(),
+            infos.k(),
+            infos.rank_in(),
+            infos.rank_out(),
+            infos.dnum(),
+            infos.dsize(),
+        )
     }
-}
 
-pub trait GLWESwitchingKeyPreparedAllocBytes<B: Backend> {
-    fn glwe_switching_key_prepared_alloc_bytes(
-        &self,
-        base2k: Base2K,
-        k: TorusPrecision,
-        rank_in: Rank,
-        rank_out: Rank,
-        dnum: Dnum,
-        dsize: Dsize,
-    ) -> usize;
-}
-
-impl<B: Backend> GLWESwitchingKeyPreparedAllocBytes<B> for Module<B>
-where
-    Module<B>: GGLWEPreparedAllocBytes<B>,
-{
     fn glwe_switching_key_prepared_alloc_bytes(
         &self,
         base2k: Base2K,
@@ -160,31 +120,31 @@ where
     ) -> usize {
         self.gglwe_prepared_alloc_bytes(base2k, k, rank_in, rank_out, dnum, dsize)
     }
-}
 
-pub trait GLWESwitchingKeyPreparedAllocBytesFromInfos<B: Backend> {
-    fn glwe_switching_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> GLWESwitchingKeyPreparedAllocBytesFromInfos<B> for Module<B>
-where
-    Module<B>: GGLWEPreparedAllocBytesFromInfos<B>,
-{
     fn glwe_switching_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
     where
         A: GGLWEInfos,
     {
-        self.gglwe_prepared_alloc_bytes_from_infos(infos)
+        self.glwe_switching_key_prepared_alloc_bytes(
+            infos.base2k(),
+            infos.k(),
+            infos.rank_in(),
+            infos.rank_out(),
+            infos.dnum(),
+            infos.dsize(),
+        )
     }
 }
 
-impl<B: Backend> GLWESwitchingKeyPrepared<Vec<u8>, B> {
+impl<B: Backend> GLWESwitchingKeyPreparedAlloc<B> for Module<B> where Module<B>: GGLWEPreparedAlloc<B> {}
+
+impl<B: Backend> GLWESwitchingKeyPrepared<Vec<u8>, B>
+where
+    Module<B>: GLWESwitchingKeyPreparedAlloc<B>,
+{
     pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
     where
         A: GGLWEInfos,
-        Module<B>: GLWESwitchingKeyPreparedAllocFromInfos<B>,
     {
         module.glwe_switching_key_prepared_alloc_from_infos(infos)
     }
@@ -197,17 +157,13 @@ impl<B: Backend> GLWESwitchingKeyPrepared<Vec<u8>, B> {
         rank_out: Rank,
         dnum: Dnum,
         dsize: Dsize,
-    ) -> Self
-    where
-        Module<B>: GLWESwitchingKeyPreparedAlloc<B>,
-    {
+    ) -> Self {
         module.glwe_switching_key_prepared_alloc(base2k, k, rank_in, rank_out, dnum, dsize)
     }
 
     pub fn alloc_bytes_from_infos<A>(module: &Module<B>, infos: &A) -> usize
     where
         A: GGLWEInfos,
-        Module<B>: GLWESwitchingKeyPreparedAllocBytesFromInfos<B>,
     {
         module.glwe_switching_key_prepared_alloc_bytes_from_infos(infos)
     }
@@ -220,23 +176,14 @@ impl<B: Backend> GLWESwitchingKeyPrepared<Vec<u8>, B> {
         rank_out: Rank,
         dnum: Dnum,
         dsize: Dsize,
-    ) -> usize
-    where
-        Module<B>: GLWESwitchingKeyPreparedAllocBytes<B>,
-    {
+    ) -> usize {
         module.glwe_switching_key_prepared_alloc_bytes(base2k, k, rank_in, rank_out, dnum, dsize)
     }
 }
 
-pub trait GLWESwitchingKeyPrepareTmpBytes {
-    fn glwe_switching_key_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
-    where
-        A: GGLWEInfos;
-}
-
-impl<B: Backend> GLWESwitchingKeyPrepareTmpBytes for Module<B>
+pub trait GLWESwitchingKeyPrepare<B: Backend>
 where
-    Module<B>: GGLWEPrepareTmpBytes,
+    Self: GGLWEPrepare<B>,
 {
     fn glwe_switching_key_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
     where
@@ -244,28 +191,7 @@ where
     {
         self.gglwe_prepare_tmp_bytes(infos)
     }
-}
 
-impl<B: Backend> GLWESwitchingKeyPrepared<Vec<u8>, B>
-where
-    Module<B>: GGLWEPrepareTmpBytes,
-{
-    pub fn prepare_tmp_bytes(&self, module: &Module<B>) -> usize {
-        module.gglwe_prepare_tmp_bytes(self)
-    }
-}
-
-pub trait GLWESwitchingKeyPrepare<B: Backend> {
-    fn glwe_switching_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
-    where
-        R: GLWESwitchingKeyPreparedToMut<B> + GLWESwitchingKeySetMetaData,
-        O: GLWESwitchingKeyToRef + GLWESwtichingKeyGetMetaData;
-}
-
-impl<B: Backend> GLWESwitchingKeyPrepare<B> for Module<B>
-where
-    Module<B>: GGLWEPrepare<B>,
-{
     fn glwe_switching_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
     where
         R: GLWESwitchingKeyPreparedToMut<B> + GLWESwitchingKeySetMetaData,
@@ -277,6 +203,8 @@ where
     }
 }
 
+impl<B: Backend> GLWESwitchingKeyPrepare<B> for Module<B> where Self: GGLWEPrepare<B> {}
+
 impl<D: DataMut, B: Backend> GLWESwitchingKeyPrepared<D, B> {
     pub fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &mut Scratch<B>)
     where
@@ -287,6 +215,15 @@ impl<D: DataMut, B: Backend> GLWESwitchingKeyPrepared<D, B> {
     }
 }
 
+impl<B: Backend> GLWESwitchingKeyPrepared<Vec<u8>, B>
+where
+    Module<B>: GLWESwitchingKeyPrepare<B>,
+{
+    pub fn prepare_tmp_bytes(&self, module: &Module<B>) -> usize {
+        module.gglwe_prepare_tmp_bytes(self)
+    }
+}
+
 pub trait GLWESwitchingKeyPreparedToMut<B: Backend> {
     fn to_mut(&mut self) -> GLWESwitchingKeyPrepared<&mut [u8], B>;
 }
diff --git a/poulpy-core/src/layouts/prepared/gglwe_tsk.rs b/poulpy-core/src/layouts/prepared/gglwe_tsk.rs
index c6cfc90..b4cd56d 100644
--- a/poulpy-core/src/layouts/prepared/gglwe_tsk.rs
+++ b/poulpy-core/src/layouts/prepared/gglwe_tsk.rs
@@ -1,13 +1,9 @@
-use poulpy_hal::{
-    api::{VmpPMatAlloc, VmpPMatAllocBytes},
-    layouts::{Backend, Data, DataMut, DataRef, Module, Scratch},
-};
+use poulpy_hal::layouts::{Backend, Data, DataMut, DataRef, Module, Scratch};
 
 use crate::layouts::{
     Base2K, Degree, Dnum, Dsize, GGLWEInfos, GLWEInfos, LWEInfos, Rank, TensorKey, TensorKeyToRef, TorusPrecision,
-    compressed::TensorKeyCompressedToMut,
     prepared::{
-        GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepareTmpBytes, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedToMut,
+        GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedAlloc, GLWESwitchingKeyPreparedToMut,
         GLWESwitchingKeyPreparedToRef,
     },
 };
@@ -59,19 +55,36 @@ impl<D: Data, B: Backend> GGLWEInfos for TensorKeyPrepared<D, B> {
     }
 }
 
-impl<B: Backend> TensorKeyPrepared<Vec<u8>, B> {
-    pub fn alloc<A>(module: &Module<B>, infos: &A) -> Self
+pub trait TensorKeyPreparedAlloc<B: Backend>
+where
+    Self: GLWESwitchingKeyPreparedAlloc<B>,
+{
+    fn tensor_key_prepared_alloc(
+        &self,
+        base2k: Base2K,
+        k: TorusPrecision,
+        dnum: Dnum,
+        dsize: Dsize,
+        rank: Rank,
+    ) -> TensorKeyPrepared<Vec<u8>, B> {
+        let pairs: u32 = (((rank.as_u32() + 1) * rank.as_u32()) >> 1).max(1);
+        TensorKeyPrepared {
+            keys: (0..pairs)
+                .map(|_| self.glwe_switching_key_prepared_alloc(base2k, k, Rank(1), rank, dnum, dsize))
+                .collect(),
+        }
+    }
+
+    fn tensor_key_prepared_alloc_from_infos<A>(&self, infos: &A) -> TensorKeyPrepared<Vec<u8>, B>
     where
         A: GGLWEInfos,
-        Module<B>: VmpPMatAlloc<B>,
     {
         assert_eq!(
             infos.rank_in(),
             infos.rank_out(),
             "rank_in != rank_out is not supported for GGLWETensorKeyPrepared"
         );
-        Self::alloc_with(
-            module,
+        self.tensor_key_prepared_alloc(
             infos.base2k(),
             infos.k(),
             infos.dnum(),
@@ -80,56 +93,58 @@ impl<B: Backend> TensorKeyPrepared<Vec<u8>, B> {
         )
     }
 
-    pub fn alloc_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum, dsize: Dsize, rank: Rank) -> Self
+    fn tensor_key_prepared_alloc_bytes(&self, base2k: Base2K, k: TorusPrecision, rank: Rank, dnum: Dnum, dsize: Dsize) -> usize {
+        let pairs: usize = (((rank.0 + 1) * rank.0) >> 1).max(1) as usize;
+        pairs * self.glwe_switching_key_prepared_alloc_bytes(base2k, k, Rank(1), rank, dnum, dsize)
+    }
+
+    fn tensor_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
     where
-        Module<B>: VmpPMatAlloc<B>,
+        A: GGLWEInfos,
     {
-        let mut keys: Vec<GLWESwitchingKeyPrepared<Vec<u8>, B>> = Vec::new();
-        let pairs: u32 = (((rank.0 + 1) * rank.0) >> 1).max(1);
-        (0..pairs).for_each(|_| {
-            keys.push(GLWESwitchingKeyPrepared::alloc(
-                module,
-                base2k,
-                k,
-                Rank(1),
-                rank,
-                dnum,
-                dsize,
-            ));
-        });
-        Self { keys }
+        self.tensor_key_prepared_alloc_bytes(
+            infos.base2k(),
+            infos.k(),
+            infos.rank(),
+            infos.dnum(),
+            infos.dsize(),
+        )
+    }
+}
+
+impl<B: Backend> TensorKeyPreparedAlloc<B> for Module<B> where Module<B>: GLWESwitchingKeyPreparedAlloc<B> {}
+
+impl<B: Backend> TensorKeyPrepared<Vec<u8>, B>
+where
+    Module<B>: TensorKeyPreparedAlloc<B>,
+{
+    pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
+    where
+        A: GGLWEInfos,
+    {
+        module.tensor_key_prepared_alloc_from_infos(infos)
+    }
+
+    pub fn alloc_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum, dsize: Dsize, rank: Rank) -> Self {
+        module.tensor_key_prepared_alloc(base2k, k, dnum, dsize, rank)
     }
 
     pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
     where
         A: GGLWEInfos,
-        Module<B>: VmpPMatAllocBytes,
     {
-        assert_eq!(
-            infos.rank_in(),
-            infos.rank_out(),
-            "rank_in != rank_out is not supported for GGLWETensorKey"
-        );
-        let rank_out: usize = infos.rank_out().into();
-        let pairs: usize = (((rank_out + 1) * rank_out) >> 1).max(1);
-        pairs
-            * GLWESwitchingKeyPrepared::alloc_bytes(
-                module,
-                infos.base2k(),
-                infos.k(),
-                Rank(1),
-                infos.rank_out(),
-                infos.dnum(),
-                infos.dsize(),
-            )
+        module.tensor_key_prepared_alloc_bytes_from_infos(infos)
     }
 
-    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank: Rank, dnum: Dnum, dsize: Dsize) -> usize
-    where
-        Module<B>: VmpPMatAllocBytes,
-    {
-        let pairs: usize = (((rank.0 + 1) * rank.0) >> 1).max(1) as usize;
-        pairs * GLWESwitchingKeyPrepared::alloc_bytes(module, base2k, k, Rank(1), rank, dnum, dsize)
+    pub fn alloc_bytes_with(
+        module: &Module<B>,
+        base2k: Base2K,
+        k: TorusPrecision,
+        rank: Rank,
+        dnum: Dnum,
+        dsize: Dsize,
+    ) -> usize {
+        module.tensor_key_prepared_alloc_bytes(base2k, k, rank, dnum, dsize)
     }
 }
 
@@ -155,22 +170,38 @@ impl<D: DataRef, B: Backend> TensorKeyPrepared<D, B> {
     }
 }
 
-pub trait TensorKeyPrepareTmpBytes {
-    fn tensor_key_prepare_tmp_bytes<A>(&self, infos: &A) -> usize;
-}
-
-impl<B: Backend> TensorKeyPrepareTmpBytes for Module<B>
+pub trait TensorKeyPrepare<B: Backend>
 where
-    Module<B>: GLWESwitchingKeyPrepareTmpBytes,
+    Self: GLWESwitchingKeyPrepare<B>,
 {
-    fn tensor_key_prepare_tmp_bytes<A>(&self, infos: &A) -> usize {
+    fn tensor_key_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
+    where
+        A: GGLWEInfos,
+    {
         self.glwe_switching_key_prepare_tmp_bytes(infos)
     }
+
+    fn tensor_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
+    where
+        R: TensorKeyPreparedToMut<B>,
+        O: TensorKeyToRef,
+    {
+        let mut res: TensorKeyPrepared<&mut [u8], B> = res.to_mut();
+        let other: TensorKey<&[u8]> = other.to_ref();
+
+        assert_eq!(res.keys.len(), other.keys.len());
+
+        for (a, b) in res.keys.iter_mut().zip(other.keys.iter()) {
+            self.glwe_switching_prepare(a, b, scratch);
+        }
+    }
 }
 
+impl<B: Backend> TensorKeyPrepare<B> for Module<B> where Module<B>: GLWESwitchingKeyPrepare<B> {}
+
 impl<B: Backend> TensorKeyPrepared<Vec<u8>, B>
 where
-    Module<B>: TensorKeyPrepareTmpBytes,
+    Module<B>: TensorKeyPrepare<B>,
 {
     fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A) -> usize
     where
@@ -180,33 +211,6 @@ where
     }
 }
 
-pub trait TensorKeyPrepare<B: Backend> {
-    fn tensor_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
-    where
-        R: TensorKeyPreparedToMut<B>,
-        O: TensorKeyToRef;
-}
-
-impl<B: Backend> TensorKeyPrepare<B> for Module<B>
-where
-    Module<B>: GLWESwitchingKeyPrepare<B>,
-{
-    fn tensor_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
-    where
-        R: TensorKeyPreparedToMut<B>,
-        O: TensorKeyToRef,
-    {
-        let res = res.to_mut();
-        let other = other.to_ref();
-
-        assert_eq!(self.keys.len(), other.keys.len());
-
-        for (a, b) in res.keys.iter_mut().zip(other.keys.iter()) {
-            self.glwe_switching_prepare(a, b, scratch);
-        }
-    }
-}
-
 impl<D: DataMut, B: Backend> TensorKeyPrepared<D, B>
 where
     Module<B>: TensorKeyPrepare<B>,
@@ -219,35 +223,6 @@ where
     }
 }
 
-pub trait TensorKeyPrepareAlloc<B: Backend> {
-    fn tensor_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: TensorKeyToRef;
-}
-
-impl<B: Backend> TensorKeyPrepareAlloc<B> for Module<B>
-where
-    Module<B>: TensorKeyPrepare<B>,
-{
-    fn tensor_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: TensorKeyToRef,
-    {
-        let mut ct_prepared: TensorKeyPrepared<Vec<u8>, B> = TensorKeyPrepared::alloc(self, other);
-        self.tensor_key_prepare(ct_prepared, other, scratch);
-        ct_prepared
-    }
-}
-
-impl<D: DataRef> TensorKey<D> {
-    pub fn prepare_alloc<B: Backend>(&self, module: &Module<B>, scratch: &Scratch<B>)
-    where
-        Module<B>: TensorKeyPrepareAlloc<B>,
-    {
-        module.tensor_key_prepare_alloc(self, scratch);
-    }
-}
-
 pub trait TensorKeyPreparedToMut<B: Backend> {
     fn to_mut(&mut self) -> TensorKeyPrepared<&mut [u8], B>;
 }
diff --git a/poulpy-core/src/layouts/prepared/ggsw_ct.rs b/poulpy-core/src/layouts/prepared/ggsw_ct.rs
index 120c9ed..da9c5db 100644
--- a/poulpy-core/src/layouts/prepared/ggsw_ct.rs
+++ b/poulpy-core/src/layouts/prepared/ggsw_ct.rs
@@ -1,11 +1,10 @@
 use poulpy_hal::{
     api::{VmpPMatAlloc, VmpPMatAllocBytes, VmpPrepare, VmpPrepareTmpBytes},
     layouts::{Backend, Data, DataMut, DataRef, Module, Scratch, VmpPMat, VmpPMatToMut, VmpPMatToRef, ZnxInfos},
-    oep::VmpPMatAllocBytesImpl,
 };
 
 use crate::layouts::{
-    Base2K, BuildError, Degree, Dnum, Dsize, GGSW, GGSWInfos, GGSWToMut, GGSWToRef, GLWEInfos, LWEInfos, Rank, TorusPrecision,
+    Base2K, Degree, Dnum, Dsize, GGSW, GGSWInfos, GGSWToRef, GLWEInfos, GetDegree, LWEInfos, Rank, TorusPrecision,
 };
 
 #[derive(PartialEq, Eq)]
@@ -50,143 +49,18 @@ impl<D: Data, B: Backend> GGSWInfos for GGSWPrepared<D, B> {
     }
 }
 
-pub struct GGSWCiphertextPreparedBuilder<D: Data, B: Backend> {
-    data: Option<VmpPMat<D, B>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-    dsize: Option<Dsize>,
-}
-
-impl<D: Data, B: Backend> GGSWPrepared<D, B> {
-    #[inline]
-    pub fn builder() -> GGSWCiphertextPreparedBuilder<D, B> {
-        GGSWCiphertextPreparedBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-            dsize: None,
-        }
-    }
-}
-
-impl<B: Backend> GGSWCiphertextPreparedBuilder<Vec<u8>, B> {
-    #[inline]
-    pub fn layout<A>(mut self, infos: &A) -> Self
-    where
-        A: GGSWInfos,
-        B: VmpPMatAllocBytesImpl<B>,
-    {
-        debug_assert!(
-            infos.size() as u32 > infos.dsize().0,
-            "invalid ggsw: ceil(k/base2k): {} <= dsize: {}",
-            infos.size(),
-            infos.dsize()
-        );
-
-        assert!(
-            infos.dnum().0 * infos.dsize().0 <= infos.size() as u32,
-            "invalid ggsw: dnum: {} * dsize:{} > ceil(k/base2k): {}",
-            infos.dnum(),
-            infos.dsize(),
-            infos.size(),
-        );
-
-        self.data = Some(VmpPMat::alloc(
-            infos.n().into(),
-            infos.dnum().into(),
-            (infos.rank() + 1).into(),
-            (infos.rank() + 1).into(),
-            infos.size(),
-        ));
-        self.base2k = Some(infos.base2k());
-        self.k = Some(infos.k());
-        self.dsize = Some(infos.dsize());
-        self
-    }
-}
-
-impl<D: Data, B: Backend> GGSWCiphertextPreparedBuilder<D, B> {
-    #[inline]
-    pub fn data(mut self, data: VmpPMat<D, B>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    #[inline]
-    pub fn dsize(mut self, dsize: Dsize) -> Self {
-        self.dsize = Some(dsize);
-        self
-    }
-
-    pub fn build(self) -> Result<GGSWPrepared<D, B>, BuildError> {
-        let data: VmpPMat<D, B> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-        let dsize: Dsize = self.dsize.ok_or(BuildError::MissingDigits)?;
-
-        if base2k == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if dsize == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k == 0_u32 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() == 0 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GGSWPrepared {
-            data,
-            base2k,
-            k,
-            dsize,
-        })
-    }
-}
-
-impl<B: Backend> GGSWPrepared<Vec<u8>, B> {
-    pub fn alloc<A>(module: &Module<B>, infos: &A) -> Self
-    where
-        A: GGSWInfos,
-        Module<B>: VmpPMatAlloc<B>,
-    {
-        Self::alloc_with(
-            module,
-            infos.base2k(),
-            infos.k(),
-            infos.dnum(),
-            infos.dsize(),
-            infos.rank(),
-        )
-    }
-
-    pub fn alloc_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum, dsize: Dsize, rank: Rank) -> Self
-    where
-        Module<B>: VmpPMatAlloc<B>,
-    {
+pub trait GGSWPreparedAlloc<B: Backend>
+where
+    Self: GetDegree + VmpPMatAlloc<B> + VmpPMatAllocBytes,
+{
+    fn ggsw_prepared_alloc(
+        &self,
+        base2k: Base2K,
+        k: TorusPrecision,
+        dnum: Dnum,
+        dsize: Dsize,
+        rank: Rank,
+    ) -> GGSWPrepared<Vec<u8>, B> {
         let size: usize = k.0.div_ceil(base2k.0) as usize;
         debug_assert!(
             size as u32 > dsize.0,
@@ -201,8 +75,8 @@ impl<B: Backend> GGSWPrepared<Vec<u8>, B> {
             dsize.0,
         );
 
-        Self {
-            data: module.vmp_pmat_alloc(
+        GGSWPrepared {
+            data: self.vmp_pmat_alloc(
                 dnum.into(),
                 (rank + 1).into(),
                 (rank + 1).into(),
@@ -214,13 +88,12 @@ impl<B: Backend> GGSWPrepared<Vec<u8>, B> {
         }
     }
 
-    pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
+    fn ggsw_prepared_alloc_from_infos<A>(&self, infos: &A) -> GGSWPrepared<Vec<u8>, B>
     where
         A: GGSWInfos,
-        Module<B>: VmpPMatAllocBytes,
     {
-        Self::alloc_bytes_with(
-            module,
+        assert_eq!(self.n(), infos.n());
+        self.ggsw_prepared_alloc(
             infos.base2k(),
             infos.k(),
             infos.dnum(),
@@ -229,10 +102,7 @@ impl<B: Backend> GGSWPrepared<Vec<u8>, B> {
         )
     }
 
-    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum, dsize: Dsize, rank: Rank) -> usize
-    where
-        Module<B>: VmpPMatAllocBytes,
-    {
+    fn ggsw_prepared_alloc_bytes(&self, base2k: Base2K, k: TorusPrecision, dnum: Dnum, dsize: Dsize, rank: Rank) -> usize {
         let size: usize = k.0.div_ceil(base2k.0) as usize;
         debug_assert!(
             size as u32 > dsize.0,
@@ -247,7 +117,57 @@ impl<B: Backend> GGSWPrepared<Vec<u8>, B> {
             dsize.0,
         );
 
-        module.vmp_pmat_alloc_bytes(dnum.into(), (rank + 1).into(), (rank + 1).into(), size)
+        self.vmp_pmat_alloc_bytes(dnum.into(), (rank + 1).into(), (rank + 1).into(), size)
+    }
+
+    fn ggsw_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
+    where
+        A: GGSWInfos,
+    {
+        assert_eq!(self.n(), infos.n());
+        self.ggsw_prepared_alloc_bytes(
+            infos.base2k(),
+            infos.k(),
+            infos.dnum(),
+            infos.dsize(),
+            infos.rank(),
+        )
+    }
+}
+
+impl<B: Backend> GGSWPreparedAlloc<B> for Module<B> where Module<B>: GetDegree + VmpPMatAlloc<B> + VmpPMatAllocBytes {}
+
+impl<B: Backend> GGSWPrepared<Vec<u8>, B>
+where
+    Module<B>: GGSWPreparedAlloc<B>,
+{
+    pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
+    where
+        A: GGSWInfos,
+    {
+        module.ggsw_prepared_alloc_from_infos(infos)
+    }
+
+    pub fn alloc(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum, dsize: Dsize, rank: Rank) -> Self {
+        module.ggsw_prepared_alloc(base2k, k, dnum, dsize, rank)
+    }
+
+    pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
+    where
+        A: GGSWInfos,
+    {
+        module.ggsw_prepared_alloc_bytes_from_infos(infos)
+    }
+
+    pub fn alloc_bytes_with(
+        module: &Module<B>,
+        base2k: Base2K,
+        k: TorusPrecision,
+        dnum: Dnum,
+        dsize: Dsize,
+        rank: Rank,
+    ) -> usize {
+        module.ggsw_prepared_alloc_bytes(base2k, k, dnum, dsize, rank)
     }
 }
 
@@ -257,20 +177,15 @@ impl<D: DataRef, B: Backend> GGSWPrepared<D, B> {
     }
 }
 
-pub trait GGSWPrepareTmpBytes {
-    fn ggsw_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
-    where
-        A: GGSWInfos;
-}
-
-impl<B: Backend> GGSWPrepareTmpBytes for Module<B>
+pub trait GGSWPrepare<B: Backend>
 where
-    Module<B>: VmpPrepareTmpBytes,
+    Self: GetDegree + VmpPrepareTmpBytes + VmpPrepare<B>,
 {
     fn ggsw_prepare_tmp_bytes<A>(&self, infos: &A) -> usize
     where
         A: GGSWInfos,
     {
+        assert_eq!(self.n(), infos.n());
         self.vmp_prepare_tmp_bytes(
             infos.dnum().into(),
             (infos.rank() + 1).into(),
@@ -278,31 +193,6 @@ where
             infos.size(),
         )
     }
-}
-
-impl<B: Backend> GGSWPrepared<Vec<u8>, B>
-where
-    Module<B>: GGSWPrepareTmpBytes,
-{
-    pub fn prepare_tmp_bytes<A>(&self, module: Module<B>, infos: &A) -> usize
-    where
-        A: GGSWInfos,
-    {
-        module.ggsw_prepare_tmp_bytes(self)
-    }
-}
-
-pub trait GGSWPrepare<B: Backend> {
-    fn ggsw_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
-    where
-        R: GGSWPreparedToMut<B>,
-        O: GGSWToRef;
-}
-
-impl<B: Backend> GGSWPrepare<B> for Module<B>
-where
-    Module<B>: VmpPrepare<B>,
-{
     fn ggsw_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
     where
         R: GGSWPreparedToMut<B>,
@@ -310,6 +200,8 @@ where
     {
         let mut res: GGSWPrepared<&mut [u8], B> = res.to_mut();
         let other: GGSW<&[u8]> = other.to_ref();
+        assert_eq!(res.n(), self.n());
+        assert_eq!(other.n(), self.n());
         assert_eq!(res.k, other.k);
         assert_eq!(res.base2k, other.base2k);
         assert_eq!(res.dsize, other.dsize);
@@ -317,6 +209,20 @@ where
     }
 }
 
+impl<B: Backend> GGSWPrepare<B> for Module<B> where Self: GetDegree + VmpPrepareTmpBytes + VmpPrepare<B> {}
+
+impl<B: Backend> GGSWPrepared<Vec<u8>, B>
+where
+    Module<B>: GGSWPrepare<B>,
+{
+    pub fn prepare_tmp_bytes<A>(&self, module: Module<B>, infos: &A) -> usize
+    where
+        A: GGSWInfos,
+    {
+        module.ggsw_prepare_tmp_bytes(infos)
+    }
+}
+
 impl<D: DataMut, B: Backend> GGSWPrepared<D, B>
 where
     Module<B>: GGSWPrepare<B>,
@@ -329,35 +235,6 @@ where
     }
 }
 
-pub trait GGSWPrepareAlloc<B: Backend> {
-    fn ggsw_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: GGSWToRef;
-}
-
-impl<B: Backend> GGSWPrepareAlloc<B> for Module<B>
-where
-    Module<B>: GGSWPrepare<B>,
-{
-    fn ggsw_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: GGSWToRef,
-    {
-        let mut ct_prepared: GGSWPrepared<Vec<u8>, B> = GGSWPrepared::alloc(self, other);
-        self.ggsw_prepare(&mut ct_prepared, other, scratch);
-        ct_prepared
-    }
-}
-
-impl<D: DataRef> GGSW<D> {
-    fn prepare_alloc<B: Backend>(&self, module: &Module<B>, scratch: &mut Scratch<B>)
-    where
-        Module<B>: GGSWPrepareAlloc<B>,
-    {
-        module.ggsw_prepare_alloc(self, scratch);
-    }
-}
-
 pub trait GGSWPreparedToMut<B: Backend> {
     fn to_mut(&mut self) -> GGSWPrepared<&mut [u8], B>;
 }
@@ -383,7 +260,7 @@ impl<D: DataRef, B: Backend> GGSWCiphertextPreparedToRef<B> for GGSWPrepared<D,
             base2k: self.base2k,
             k: self.k,
             dsize: self.dsize,
-            data: self.data.to_mut(),
+            data: self.data.to_ref(),
         }
     }
 }
diff --git a/poulpy-core/src/layouts/prepared/glwe_pk.rs b/poulpy-core/src/layouts/prepared/glwe_pk.rs
index f730cf8..4ad2be6 100644
--- a/poulpy-core/src/layouts/prepared/glwe_pk.rs
+++ b/poulpy-core/src/layouts/prepared/glwe_pk.rs
@@ -1,12 +1,11 @@
 use poulpy_hal::{
     api::{VecZnxDftAlloc, VecZnxDftAllocBytes, VecZnxDftApply},
-    layouts::{Backend, Data, DataMut, DataRef, Module, Scratch, VecZnxDft, VecZnxDftToMut, VecZnxDftToRef, ZnxInfos},
-    oep::VecZnxDftAllocBytesImpl,
+    layouts::{Backend, Data, DataMut, DataRef, Module, VecZnxDft, VecZnxDftToMut, VecZnxDftToRef, ZnxInfos},
 };
 
 use crate::{
     dist::Distribution,
-    layouts::{Base2K, BuildError, Degree, GLWEInfos, GLWEPublicKey, GLWEPublicKeyToRef, LWEInfos, Rank, TorusPrecision},
+    layouts::{Base2K, Degree, GLWEInfos, GLWEPublicKey, GLWEPublicKeyToRef, GetDegree, GetDist, LWEInfos, Rank, TorusPrecision},
 };
 
 #[derive(PartialEq, Eq)]
@@ -51,229 +50,106 @@ impl<D: Data, B: Backend> GLWEInfos for GLWEPublicKeyPrepared<D, B> {
     }
 }
 
-pub struct GLWEPublicKeyPreparedBuilder<D: Data, B: Backend> {
-    data: Option<VecZnxDft<D, B>>,
-    base2k: Option<Base2K>,
-    k: Option<TorusPrecision>,
-}
-
-impl<D: Data, B: Backend> GLWEPublicKeyPrepared<D, B> {
-    #[inline]
-    pub fn builder() -> GLWEPublicKeyPreparedBuilder<D, B> {
-        GLWEPublicKeyPreparedBuilder {
-            data: None,
-            base2k: None,
-            k: None,
-        }
-    }
-}
-
-impl<B: Backend> GLWEPublicKeyPreparedBuilder<Vec<u8>, B> {
-    #[inline]
-    pub fn layout<A>(mut self, layout: &A) -> Self
-    where
-        A: GLWEInfos,
-        B: VecZnxDftAllocBytesImpl<B>,
-    {
-        self.data = Some(VecZnxDft::alloc(
-            layout.n().into(),
-            (layout.rank() + 1).into(),
-            layout.size(),
-        ));
-        self.base2k = Some(layout.base2k());
-        self.k = Some(layout.k());
-        self
-    }
-}
-
-impl<D: Data, B: Backend> GLWEPublicKeyPreparedBuilder<D, B> {
-    #[inline]
-    pub fn data(mut self, data: VecZnxDft<D, B>) -> Self {
-        self.data = Some(data);
-        self
-    }
-    #[inline]
-    pub fn base2k(mut self, base2k: Base2K) -> Self {
-        self.base2k = Some(base2k);
-        self
-    }
-    #[inline]
-    pub fn k(mut self, k: TorusPrecision) -> Self {
-        self.k = Some(k);
-        self
-    }
-
-    pub fn build(self) -> Result<GLWEPublicKeyPrepared<D, B>, BuildError> {
-        let data: VecZnxDft<D, B> = self.data.ok_or(BuildError::MissingData)?;
-        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
-        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
-
-        if base2k == 0_u32 {
-            return Err(BuildError::ZeroBase2K);
-        }
-
-        if k == 0_u32 {
-            return Err(BuildError::ZeroTorusPrecision);
-        }
-
-        if data.n() == 0 {
-            return Err(BuildError::ZeroDegree);
-        }
-
-        if data.cols() == 0 {
-            return Err(BuildError::ZeroCols);
-        }
-
-        if data.size() == 0 {
-            return Err(BuildError::ZeroLimbs);
-        }
-
-        Ok(GLWEPublicKeyPrepared {
-            data,
-            base2k,
-            k,
-            dist: Distribution::NONE,
-        })
-    }
-}
-
-impl<B: Backend> GLWEPublicKeyPrepared<Vec<u8>, B> {
-    pub fn alloc<A>(module: &Module<B>, infos: &A) -> Self
-    where
-        A: GLWEInfos,
-        Module<B>: VecZnxDftAlloc<B>,
-    {
-        debug_assert_eq!(module.n(), infos.n().0 as usize, "module.n() != infos.n()");
-        Self::alloc_with(module, infos.base2k(), infos.k(), infos.rank())
-    }
-
-    pub fn alloc_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank: Rank) -> Self
-    where
-        Module<B>: VecZnxDftAlloc<B>,
-    {
-        Self {
-            data: module.vec_znx_dft_alloc((rank + 1).into(), k.0.div_ceil(base2k.0) as usize),
-            base2k,
-            k,
-            dist: Distribution::NONE,
-        }
-    }
-
-    pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
-    where
-        A: GLWEInfos,
-        Module<B>: VecZnxDftAllocBytes,
-    {
-        debug_assert_eq!(module.n(), infos.n().0 as usize, "module.n() != infos.n()");
-        Self::alloc_bytes_with(module, infos.base2k(), infos.k(), infos.rank())
-    }
-
-    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank: Rank) -> usize
-    where
-        Module<B>: VecZnxDftAllocBytes,
-    {
-        module.vec_znx_dft_alloc_bytes((rank + 1).into(), k.0.div_ceil(base2k.0) as usize)
-    }
-}
-
-pub trait GLWEPublicKeyPrepareTmpBytes {
-    fn glwe_public_key_prepare_tmp_bytes<A>(&self, infos: &A)
-    where
-        A: GLWEInfos;
-}
-
-impl<B: Backend> GLWEPublicKeyPrepareTmpBytes for Module<B> {
-    fn glwe_public_key_prepare_tmp_bytes<A>(&self, infos: &A)
-    where
-        A: GLWEInfos,
-    {
-        0
-    }
-}
-
-impl<B: Backend> GLWEPublicKeyPrepared<Vec<u8>, B> {
-    pub fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A)
-    where
-        A: GLWEInfos,
-        Module<B>: GLWEPublicKeyPrepareTmpBytes,
-    {
-        module.glwe_public_key_prepare_tmp_bytes(infos);
-    }
-}
-
-pub trait GLWEPublicKeyPrepare<B: Backend> {
-    fn glwe_public_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
-    where
-        R: GLWEPublicKeyPreparedToMut<B> + SetDist,
-        O: GLWEPublicKeyToRef;
-}
-
-impl<B: Backend> GLWEPublicKeyPrepare<B> for Module<B>
+pub trait GLWEPublicKeyPreparedAlloc<B: Backend>
 where
-    Module<B>: VecZnxDftAlloc<B> + VecZnxDftApply<B>,
+    Self: GetDegree + VecZnxDftAlloc<B> + VecZnxDftAllocBytes,
 {
-    fn glwe_public_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
+    fn glwe_public_key_prepared_alloc(&self, base2k: Base2K, k: TorusPrecision, rank: Rank) -> GLWEPublicKeyPrepared<Vec<u8>, B> {
+        GLWEPublicKeyPrepared {
+            data: self.vec_znx_dft_alloc((rank + 1).into(), k.0.div_ceil(base2k.0) as usize),
+            base2k,
+            k,
+            dist: Distribution::NONE,
+        }
+    }
+
+    fn glwe_public_key_alloc_from_infos<A>(&self, infos: &A) -> GLWEPublicKeyPrepared<Vec<u8>, B>
+    where
+        A: GLWEInfos,
+    {
+        self.glwe_public_key_prepared_alloc(infos.base2k(), infos.k(), infos.rank())
+    }
+
+    fn glwe_public_key_prepared_alloc_bytes(&self, base2k: Base2K, k: TorusPrecision, rank: Rank) -> usize {
+        self.vec_znx_dft_alloc_bytes((rank + 1).into(), k.0.div_ceil(base2k.0) as usize)
+    }
+
+    fn glwe_public_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
+    where
+        A: GLWEInfos,
+    {
+        self.glwe_public_key_prepared_alloc_bytes(infos.base2k(), infos.k(), infos.rank())
+    }
+}
+
+impl<B: Backend> GLWEPublicKeyPreparedAlloc<B> for Module<B> where Self: VecZnxDftAlloc<B> + VecZnxDftAllocBytes {}
+
+impl<B: Backend> GLWEPublicKeyPrepared<Vec<u8>, B>
+where
+    Module<B>: GLWEPublicKeyPreparedAlloc<B>,
+{
+    pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
+    where
+        A: GLWEInfos,
+    {
+        module.glwe_public_key_alloc_from_infos(infos)
+    }
+
+    pub fn alloc(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank: Rank) -> Self {
+        module.glwe_public_key_prepared_alloc(base2k, k, rank)
+    }
+
+    pub fn alloc_bytes_from_infos<A>(module: &Module<B>, infos: &A) -> usize
+    where
+        A: GLWEInfos,
+    {
+        module.glwe_public_key_prepared_alloc_bytes_from_infos(infos)
+    }
+
+    pub fn alloc_bytes(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank: Rank) -> usize {
+        module.glwe_public_key_prepared_alloc_bytes(base2k, k, rank)
+    }
+}
+
+pub trait GLWEPublicKeyPrepare<B: Backend>
+where
+    Self: GetDegree + VecZnxDftApply<B>,
+{
+    fn glwe_public_key_prepare<R, O>(&self, res: &mut R, other: &O)
     where
         R: GLWEPublicKeyPreparedToMut<B> + SetDist,
-        O: GLWEPublicKeyToRef,
+        O: GLWEPublicKeyToRef + GetDist,
     {
         {
-            let res: GLWEPublicKeyPrepared<&mut [u8], B> = res.to_mut();
+            let mut res: GLWEPublicKeyPrepared<&mut [u8], B> = res.to_mut();
             let other: GLWEPublicKey<&[u8]> = other.to_ref();
 
-            assert_eq!(res.n(), self.n() as u32);
-            assert_eq!(other.n(), self.n() as u32);
+            assert_eq!(res.n(), self.n());
+            assert_eq!(other.n(), self.n());
             assert_eq!(res.size(), other.size());
             assert_eq!(res.k(), other.k());
             assert_eq!(res.base2k(), other.base2k());
 
-            for i in 0..(self.rank() + 1).into() {
-                self.vec_znx_dft_apply(1, 0, &mut self.data, i, &other.data, i);
+            for i in 0..(res.rank() + 1).into() {
+                self.vec_znx_dft_apply(1, 0, &mut res.data, i, &other.data, i);
             }
         }
 
-        res.set_dist(other.dist);
+        res.set_dist(other.get_dist());
     }
 }
 
+impl<B: Backend> GLWEPublicKeyPrepare<B> for Module<B> where Self: GetDegree + VecZnxDftApply<B> {}
+
 impl<D: DataMut, B: Backend> GLWEPublicKeyPrepared<D, B>
 where
     Module<B>: GLWEPublicKeyPrepare<B>,
 {
-    pub fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &mut Scratch<B>)
+    pub fn prepare<O>(&mut self, module: &Module<B>, other: &O)
     where
-        O: GLWEPublicKeyToRef,
+        O: GLWEPublicKeyToRef + GetDist,
     {
-        module.glwe_public_key_prepare(self, other, scratch);
-    }
-}
-
-pub trait GLWEPublicKeyPrepareAlloc<B: Backend> {
-    fn glwe_public_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: GLWEPublicKeyToRef;
-}
-
-impl<B: Backend> GLWEPublicKeyPrepareAlloc<B> for Module<B>
-where
-    Module<B>: GLWEPublicKeyPrepare<B>,
-{
-    fn glwe_public_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: GLWEPublicKeyToRef,
-    {
-        let mut ct_prepared: GLWEPublicKeyPrepared<Vec<u8>, B> = GLWEPublicKeyPrepared::alloc(self, other);
-        self.glwe_public_key_prepare(&mut ct_prepared, ct_prepared, scratch);
-        ct_prepared
-    }
-}
-
-impl<D: DataRef> GLWEPublicKey<D> {
-    pub fn prepare_alloc<B: Backend>(&self, module: &Module<B>, scratch: &mut Scratch<B>)
-    where
-        Module<B>: GLWEPublicKeyPrepareAlloc<B>,
-    {
-        module.glwe_public_key_prepare_alloc(self, scratch);
+        module.glwe_public_key_prepare(self, other);
     }
 }
 
diff --git a/poulpy-core/src/layouts/prepared/glwe_sk.rs b/poulpy-core/src/layouts/prepared/glwe_sk.rs
index c75f425..4bac6c0 100644
--- a/poulpy-core/src/layouts/prepared/glwe_sk.rs
+++ b/poulpy-core/src/layouts/prepared/glwe_sk.rs
@@ -1,12 +1,12 @@
 use poulpy_hal::{
     api::{SvpPPolAlloc, SvpPPolAllocBytes, SvpPrepare},
-    layouts::{Backend, Data, DataMut, DataRef, Module, Scratch, SvpPPol, SvpPPolToMut, SvpPPolToRef, ZnxInfos},
+    layouts::{Backend, Data, DataMut, DataRef, Module, SvpPPol, SvpPPolToMut, SvpPPolToRef, ZnxInfos},
 };
 
 use crate::{
     dist::Distribution,
     layouts::{
-        Base2K, Degree, GLWEInfos, GLWESecret, GLWESecretToMut, GLWESecretToRef, LWEInfos, Rank, TorusPrecision,
+        Base2K, Degree, GLWEInfos, GLWESecret, GLWESecretToRef, GetDegree, GetDist, LWEInfos, Rank, TorusPrecision,
         prepared::SetDist,
     },
 };
@@ -44,40 +44,63 @@ impl<D: Data, B: Backend> GLWEInfos for GLWESecretPrepared<D, B> {
         Rank(self.data.cols() as u32)
     }
 }
-impl<B: Backend> GLWESecretPrepared<Vec<u8>, B> {
-    pub fn alloc<A>(module: &Module<B>, infos: &A) -> Self
-    where
-        A: GLWEInfos,
-        Module<B>: SvpPPolAlloc<B>,
-    {
-        assert_eq!(module.n() as u32, infos.n());
-        Self::alloc_with(module, infos.rank())
-    }
 
-    pub fn alloc_with(module: &Module<B>, rank: Rank) -> Self
-    where
-        Module<B>: SvpPPolAlloc<B>,
-    {
-        Self {
-            data: module.svp_ppol_alloc(rank.into()),
+pub trait GLWESecretPreparedAlloc<B: Backend>
+where
+    Self: GetDegree + SvpPPolAllocBytes + SvpPPolAlloc<B>,
+{
+    fn glwe_secret_prepared_alloc(&self, rank: Rank) -> GLWESecretPrepared<Vec<u8>, B> {
+        GLWESecretPrepared {
+            data: self.svp_ppol_alloc(rank.into()),
             dist: Distribution::NONE,
         }
     }
-
-    pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
+    fn glwe_secret_prepared_alloc_from_infos<A>(&self, infos: &A) -> GLWESecretPrepared<Vec<u8>, B>
     where
         A: GLWEInfos,
-        Module<B>: SvpPPolAllocBytes,
     {
-        assert_eq!(module.n() as u32, infos.n());
-        Self::alloc_bytes_with(module, infos.rank())
+        assert_eq!(self.n(), infos.n());
+        self.glwe_secret_prepared_alloc(infos.rank())
     }
 
-    pub fn alloc_bytes_with(module: &Module<B>, rank: Rank) -> usize
+    fn glwe_secret_alloc_bytes(&self, rank: Rank) -> usize {
+        self.svp_ppol_alloc_bytes(rank.into())
+    }
+    fn glwe_secret_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
     where
-        Module<B>: SvpPPolAllocBytes,
+        A: GLWEInfos,
     {
-        module.svp_ppol_alloc_bytes(rank.into())
+        assert_eq!(self.n(), infos.n());
+        self.glwe_secret_alloc_bytes(infos.rank())
+    }
+}
+
+impl<B: Backend> GLWESecretPreparedAlloc<B> for Module<B> where Self: GetDegree + SvpPPolAllocBytes + SvpPPolAlloc<B> {}
+
+impl<B: Backend> GLWESecretPrepared<Vec<u8>, B>
+where
+    Module<B>: GLWESecretPreparedAlloc<B>,
+{
+    pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
+    where
+        A: GLWEInfos,
+    {
+        module.glwe_secret_prepared_alloc_from_infos(infos)
+    }
+
+    pub fn alloc(module: &Module<B>, rank: Rank) -> Self {
+        module.glwe_secret_prepared_alloc(rank)
+    }
+
+    pub fn alloc_bytes_from_infos<A>(module: &Module<B>, infos: &A) -> usize
+    where
+        A: GLWEInfos,
+    {
+        module.glwe_secret_alloc_bytes_from_infos(infos)
+    }
+
+    pub fn alloc_bytes(module: &Module<B>, rank: Rank) -> usize {
+        module.glwe_secret_alloc_bytes(rank)
     }
 }
 
@@ -91,81 +114,29 @@ impl<D: Data, B: Backend> GLWESecretPrepared<D, B> {
     }
 }
 
-pub trait GLWESecretPrepareTmpBytes {
-    fn glwe_secret_prepare_tmp_bytes<A>(&self, infos: &A)
-    where
-        A: GLWEInfos;
-}
-
-impl<B: Backend> GLWESecretPrepareTmpBytes for Module<B> {
-    fn glwe_secret_prepare_tmp_bytes<A>(&self, infos: &A)
-    where
-        A: GLWEInfos,
-    {
-        0
-    }
-}
-
-impl<B: Backend> GLWESecretPrepared<Vec<u8>, B>
+pub trait GLWESecretPrepare<B: Backend>
 where
-    Module<B>: GLWESecretPrepareTmpBytes,
+    Self: SvpPrepare<B>,
 {
-    fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A) -> usize
-    where
-        A: GLWEInfos,
-    {
-        0
-    }
-}
-
-pub trait GLWESecretPrepare<B: Backend> {
-    fn glwe_secret_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
+    fn glwe_secret_prepare<R, O>(&self, res: &mut R, other: &O)
     where
         R: GLWESecretPreparedToMut<B> + SetDist,
-        O: GLWESecretToRef;
-}
-
-impl<B: Backend> GLWESecretPrepare<B> for Module<B>
-where
-    Module<B>: SvpPrepare<B>,
-{
-    fn glwe_secret_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
-    where
-        R: GLWESecretPreparedToMut<B> + SetDist,
-        O: GLWESecretToRef,
+        O: GLWESecretToRef + GetDist,
     {
         {
-            let res: GLWESecretPrepared<&mut [u8], _> = res.to_mut();
+            let mut res: GLWESecretPrepared<&mut [u8], _> = res.to_mut();
             let other: GLWESecret<&[u8]> = other.to_ref();
 
-            for i in 0..self.rank().into() {
+            for i in 0..res.rank().into() {
                 self.svp_prepare(&mut res.data, i, &other.data, i);
             }
         }
 
-        res.set_dist(other.dist);
+        res.set_dist(other.get_dist());
     }
 }
 
-pub trait GLWESecretPrepareAlloc<B: Backend> {
-    fn glwe_secret_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: GLWESecretToMut;
-}
-
-impl<B: Backend> GLWESecretPrepareAlloc<B> for Module<B>
-where
-    Module<B>: GLWESecretPrepare<B>,
-{
-    fn glwe_secret_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: GLWESecretToMut,
-    {
-        let mut ct_prep: GLWESecretPrepared<Vec<u8>, B> = GLWESecretPrepared::alloc(self, self);
-        self.glwe_secret_prepare(&mut ct_prep, other, scratch);
-        ct_prep
-    }
-}
+impl<B: Backend> GLWESecretPrepare<B> for Module<B> where Self: SvpPrepare<B> {}
 
 pub trait GLWESecretPreparedToRef<B: Backend> {
     fn to_ref(&self) -> GLWESecretPrepared<&[u8], B>;
diff --git a/poulpy-core/src/layouts/prepared/glwe_to_lwe_ksk.rs b/poulpy-core/src/layouts/prepared/glwe_to_lwe_ksk.rs
index e2a8fdc..5f10f66 100644
--- a/poulpy-core/src/layouts/prepared/glwe_to_lwe_ksk.rs
+++ b/poulpy-core/src/layouts/prepared/glwe_to_lwe_ksk.rs
@@ -1,13 +1,9 @@
-use poulpy_hal::{
-    api::{VmpPMatAlloc, VmpPMatAllocBytes},
-    layouts::{Backend, Data, DataMut, DataRef, Module, Scratch},
-};
+use poulpy_hal::layouts::{Backend, Data, DataMut, DataRef, Module, Scratch};
 
 use crate::layouts::{
-    Base2K, Degree, Dnum, Dsize, GGLWEInfos, GLWEInfos, GLWEToLWESwitchingKeyToMut, GLWEToLWESwitchingKeyToRef, LWEInfos, Rank,
-    TorusPrecision,
+    Base2K, Degree, Dnum, Dsize, GGLWEInfos, GLWEInfos, GLWEToLWESwitchingKeyToRef, LWEInfos, Rank, TorusPrecision,
     prepared::{
-        GLWESecretPrepareTmpBytes, GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedToMut,
+        GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedAlloc, GLWESwitchingKeyPreparedToMut,
         GLWESwitchingKeyPreparedToRef,
     },
 };
@@ -57,11 +53,22 @@ impl<D: Data, B: Backend> GGLWEInfos for GLWEToLWESwitchingKeyPrepared<D, B> {
     }
 }
 
-impl<B: Backend> GLWEToLWESwitchingKeyPrepared<Vec<u8>, B> {
-    pub fn alloc<A>(module: &Module<B>, infos: &A) -> Self
+pub trait GLWEToLWESwitchingKeyPreparedAlloc<B: Backend>
+where
+    Self: GLWESwitchingKeyPreparedAlloc<B>,
+{
+    fn glwe_to_lwe_switching_key_prepared_alloc(
+        &self,
+        base2k: Base2K,
+        k: TorusPrecision,
+        rank_in: Rank,
+        dnum: Dnum,
+    ) -> GLWEToLWESwitchingKeyPrepared<Vec<u8>, B> {
+        GLWEToLWESwitchingKeyPrepared(self.glwe_switching_key_prepared_alloc(base2k, k, rank_in, Rank(1), dnum, Dsize(1)))
+    }
+    fn glwe_to_lwe_switching_key_prepared_alloc_from_infos<A>(&self, infos: &A) -> GLWEToLWESwitchingKeyPrepared<Vec<u8>, B>
     where
         A: GGLWEInfos,
-        Module<B>: VmpPMatAlloc<B>,
     {
         debug_assert_eq!(
             infos.rank_out().0,
@@ -73,28 +80,22 @@ impl<B: Backend> GLWEToLWESwitchingKeyPrepared<Vec<u8>, B> {
             1,
             "dsize > 1 is not supported for GLWEToLWESwitchingKeyPrepared"
         );
-        Self(GLWESwitchingKeyPrepared::alloc_from_infos(module, infos))
+        self.glwe_to_lwe_switching_key_prepared_alloc(infos.base2k(), infos.k(), infos.rank_in(), infos.dnum())
     }
 
-    pub fn alloc_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank_in: Rank, dnum: Dnum) -> Self
-    where
-        Module<B>: VmpPMatAlloc<B>,
-    {
-        Self(GLWESwitchingKeyPrepared::alloc(
-            module,
-            base2k,
-            k,
-            rank_in,
-            Rank(1),
-            dnum,
-            Dsize(1),
-        ))
+    fn glwe_to_lwe_switching_key_prepared_alloc_bytes(
+        &self,
+        base2k: Base2K,
+        k: TorusPrecision,
+        rank_in: Rank,
+        dnum: Dnum,
+    ) -> usize {
+        self.glwe_switching_key_prepared_alloc_bytes(base2k, k, rank_in, Rank(1), dnum, Dsize(1))
     }
 
-    pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
+    fn glwe_to_lwe_switching_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
     where
         A: GGLWEInfos,
-        Module<B>: VmpPMatAllocBytes,
     {
         debug_assert_eq!(
             infos.rank_out().0,
@@ -106,67 +107,73 @@ impl<B: Backend> GLWEToLWESwitchingKeyPrepared<Vec<u8>, B> {
             1,
             "dsize > 1 is not supported for GLWEToLWESwitchingKeyPrepared"
         );
-        GLWESwitchingKeyPrepared::alloc_bytes_from_infos(module, infos)
-    }
-
-    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank_in: Rank, dnum: Dnum) -> usize
-    where
-        Module<B>: VmpPMatAllocBytes,
-    {
-        GLWESwitchingKeyPrepared::alloc_bytes(module, base2k, k, rank_in, Rank(1), dnum, Dsize(1))
+        self.glwe_to_lwe_switching_key_prepared_alloc_bytes(infos.base2k(), infos.k(), infos.rank_in(), infos.dnum())
     }
 }
 
-pub trait GLWEToLWESwitchingKeyPrepareTmpBytes {
-    fn glwe_to_lwe_switching_key_prepare_tmp_bytes<A>(&self, infos: &A)
-    where
-        A: GGLWEInfos;
-}
+impl<B: Backend> GLWEToLWESwitchingKeyPreparedAlloc<B> for Module<B> where Module<B>: GLWESwitchingKeyPreparedAlloc<B> {}
 
-impl<B: Backend> GLWEToLWESwitchingKeyPrepareTmpBytes for Module<B>
+impl<B: Backend> GLWEToLWESwitchingKeyPrepared<Vec<u8>, B>
 where
-    Module<B>: GLWEToLWESwitchingKeyPrepareTmpBytes,
+    Module<B>: GLWEToLWESwitchingKeyPreparedAlloc<B>,
+{
+    pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
+    where
+        A: GGLWEInfos,
+    {
+        module.glwe_to_lwe_switching_key_prepared_alloc_from_infos(infos)
+    }
+
+    pub fn alloc(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank_in: Rank, dnum: Dnum) -> Self {
+        module.glwe_to_lwe_switching_key_prepared_alloc(base2k, k, rank_in, dnum)
+    }
+
+    pub fn alloc_bytes_from_infos<A>(module: &Module<B>, infos: &A) -> usize
+    where
+        A: GGLWEInfos,
+    {
+        module.glwe_to_lwe_switching_key_prepared_alloc_bytes_from_infos(infos)
+    }
+
+    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank_in: Rank, dnum: Dnum) -> usize {
+        module.glwe_to_lwe_switching_key_prepared_alloc_bytes(base2k, k, rank_in, dnum)
+    }
+}
+
+pub trait GLWEToLWESwitchingKeyPrepare<B: Backend>
+where
+    Self: GLWESwitchingKeyPrepare<B>,
 {
     fn glwe_to_lwe_switching_key_prepare_tmp_bytes<A>(&self, infos: &A)
     where
         A: GGLWEInfos,
     {
-        self.glwe_to_lwe_switching_key_prepare_tmp_bytes(infos);
+        self.glwe_switching_key_prepare_tmp_bytes(infos);
     }
-}
 
-impl<B: Backend> GLWEToLWESwitchingKeyPrepared<Vec<u8>, B> {
-    pub fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A)
-    where
-        A: GLWEInfos,
-        Module<B>: GLWEToLWESwitchingKeyPrepareTmpBytes,
-    {
-        module.glwe_secret_prepare_tmp_bytes(infos);
-    }
-}
-
-pub trait GLWEToLWESwitchingKeyPrepare<B: Backend> {
-    fn glwe_to_lwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
-    where
-        R: GLWEToLWESwitchingKeyPreparedToMut<B>,
-        O: GLWEToLWESwitchingKeyToRef;
-}
-
-impl<B: Backend> GLWEToLWESwitchingKeyPrepare<B> for Module<B>
-where
-    Module<B>: GLWESwitchingKeyPrepare<B>,
-{
-    fn glwe_to_lwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
+    fn glwe_to_lwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
     where
         R: GLWEToLWESwitchingKeyPreparedToMut<B>,
         O: GLWEToLWESwitchingKeyToRef,
     {
-        self.glwe_switching_prepare(&mut res.to_mut().0, other, scratch);
+        self.glwe_switching_prepare(&mut res.to_mut().0, &other.to_ref().0, scratch);
+    }
+}
+
+impl<B: Backend> GLWEToLWESwitchingKeyPrepare<B> for Module<B> where Self: GLWESwitchingKeyPrepare<B> {}
+
+impl<B: Backend> GLWEToLWESwitchingKeyPrepared<Vec<u8>, B> {
+    pub fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A)
+    where
+        A: GGLWEInfos,
+        Module<B>: GLWEToLWESwitchingKeyPrepare<B>,
+    {
+        module.glwe_to_lwe_switching_key_prepare_tmp_bytes(infos);
     }
 }
 
 impl<D: DataMut, B: Backend> GLWEToLWESwitchingKeyPrepared<D, B> {
-    fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &Scratch<B>)
+    fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &mut Scratch<B>)
     where
         O: GLWEToLWESwitchingKeyToRef,
         Module<B>: GLWEToLWESwitchingKeyPrepare<B>,
@@ -175,26 +182,6 @@ impl<D: DataMut, B: Backend> GLWEToLWESwitchingKeyPrepared<D, B> {
     }
 }
 
-pub trait GLWEToLWESwitchingKeyPrepareAlloc<B: Backend> {
-    fn glwe_to_lwe_switching_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: GLWEToLWESwitchingKeyToRef;
-}
-
-impl<B: Backend> GLWEToLWESwitchingKeyPrepareAlloc<B> for Module<B>
-where
-    Module<B>: GLWEToLWESwitchingKeyPrepare<B>,
-{
-    fn glwe_to_lwe_switching_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: GLWEToLWESwitchingKeyToRef,
-    {
-        let mut ct_prep: GLWEToLWESwitchingKeyPrepared<Vec<u8>, B> = GLWEToLWESwitchingKeyPrepared::alloc(self, &other.to_ref());
-        self.glwe_to_lwe_switching_key_prepare(&mut ct_prep, other, scratch);
-        ct_prep
-    }
-}
-
 pub trait GLWEToLWESwitchingKeyPreparedToRef<B: Backend> {
     fn to_ref(&self) -> GLWEToLWESwitchingKeyPrepared<&[u8], B>;
 }
diff --git a/poulpy-core/src/layouts/prepared/lwe_ksk.rs b/poulpy-core/src/layouts/prepared/lwe_ksk.rs
index cf5f31b..6017f2f 100644
--- a/poulpy-core/src/layouts/prepared/lwe_ksk.rs
+++ b/poulpy-core/src/layouts/prepared/lwe_ksk.rs
@@ -1,11 +1,11 @@
-use poulpy_hal::{
-    api::{VmpPMatAlloc, VmpPMatAllocBytes},
-    layouts::{Backend, Data, DataMut, DataRef, Module, Scratch},
-};
+use poulpy_hal::layouts::{Backend, Data, DataMut, DataRef, Module, Scratch};
 
 use crate::layouts::{
     Base2K, Degree, Dnum, Dsize, GGLWEInfos, GLWEInfos, LWEInfos, LWESwitchingKeyToRef, Rank, TorusPrecision,
-    prepared::{GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedToMut, GLWESwitchingKeyPreparedToRef},
+    prepared::{
+        GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedAlloc, GLWESwitchingKeyPreparedToMut,
+        GLWESwitchingKeyPreparedToRef,
+    },
 };
 
 #[derive(PartialEq, Eq)]
@@ -52,11 +52,22 @@ impl<D: Data, B: Backend> GGLWEInfos for LWESwitchingKeyPrepared<D, B> {
     }
 }
 
-impl<B: Backend> LWESwitchingKeyPrepared<Vec<u8>, B> {
-    pub fn alloc<A>(module: &Module<B>, infos: &A) -> Self
+pub trait LWESwitchingKeyPreparedAlloc<B: Backend>
+where
+    Self: GLWESwitchingKeyPreparedAlloc<B>,
+{
+    fn lwe_switching_key_prepared_alloc(
+        &self,
+        base2k: Base2K,
+        k: TorusPrecision,
+        dnum: Dnum,
+    ) -> LWESwitchingKeyPrepared<Vec<u8>, B> {
+        LWESwitchingKeyPrepared(self.glwe_switching_key_prepared_alloc(base2k, k, Rank(1), Rank(1), dnum, Dsize(1)))
+    }
+
+    fn lwe_switching_key_prepared_alloc_from_infos<A>(&self, infos: &A) -> LWESwitchingKeyPrepared<Vec<u8>, B>
     where
         A: GGLWEInfos,
-        Module<B>: VmpPMatAlloc<B>,
     {
         debug_assert_eq!(
             infos.dsize().0,
@@ -73,28 +84,16 @@ impl<B: Backend> LWESwitchingKeyPrepared<Vec<u8>, B> {
             1,
             "rank_out > 1 is not supported for LWESwitchingKey"
         );
-        Self(GLWESwitchingKeyPrepared::alloc_from_infos(module, infos))
+        self.lwe_switching_key_prepared_alloc(infos.base2k(), infos.k(), infos.dnum())
     }
 
-    pub fn alloc_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum) -> Self
-    where
-        Module<B>: VmpPMatAlloc<B>,
-    {
-        Self(GLWESwitchingKeyPrepared::alloc(
-            module,
-            base2k,
-            k,
-            Rank(1),
-            Rank(1),
-            dnum,
-            Dsize(1),
-        ))
+    fn lwe_switching_key_prepared_alloc_bytes(&self, base2k: Base2K, k: TorusPrecision, dnum: Dnum) -> usize {
+        self.glwe_switching_key_prepared_alloc_bytes(base2k, k, Rank(1), Rank(1), dnum, Dsize(1))
     }
 
-    pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
+    fn lwe_switching_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
     where
         A: GGLWEInfos,
-        Module<B>: VmpPMatAllocBytes,
     {
         debug_assert_eq!(
             infos.dsize().0,
@@ -111,67 +110,72 @@ impl<B: Backend> LWESwitchingKeyPrepared<Vec<u8>, B> {
             1,
             "rank_out > 1 is not supported for LWESwitchingKey"
         );
-        GLWESwitchingKeyPrepared::alloc_bytes_from_infos(module, infos)
-    }
-
-    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum) -> usize
-    where
-        Module<B>: VmpPMatAllocBytes,
-    {
-        GLWESwitchingKeyPrepared::alloc_bytes(module, base2k, k, Rank(1), Rank(1), dnum, Dsize(1))
+        self.lwe_switching_key_prepared_alloc_bytes(infos.base2k(), infos.k(), infos.dnum())
     }
 }
 
-pub trait LWESwitchingKeyPrepareTmpBytes {
-    fn lwe_switching_key_prepare_tmp_bytes<A>(&self, infos: &A)
-    where
-        A: GGLWEInfos;
-}
+impl<B: Backend> LWESwitchingKeyPreparedAlloc<B> for Module<B> where Self: GLWESwitchingKeyPreparedAlloc<B> {}
 
-impl<B: Backend> LWESwitchingKeyPrepareTmpBytes for Module<B>
+impl<B: Backend> LWESwitchingKeyPrepared<Vec<u8>, B>
 where
-    Module<B>: LWESwitchingKeyPrepareTmpBytes,
+    Module<B>: LWESwitchingKeyPreparedAlloc<B>,
+{
+    pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
+    where
+        A: GGLWEInfos,
+    {
+        module.lwe_switching_key_prepared_alloc_from_infos(infos)
+    }
+
+    pub fn alloc(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum) -> Self {
+        module.lwe_switching_key_prepared_alloc(base2k, k, dnum)
+    }
+
+    pub fn alloc_bytes_from_infos<A>(module: &Module<B>, infos: &A) -> usize
+    where
+        A: GGLWEInfos,
+    {
+        module.lwe_switching_key_prepared_alloc_bytes_from_infos(infos)
+    }
+
+    pub fn alloc_bytes(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum) -> usize {
+        module.lwe_switching_key_prepared_alloc_bytes(base2k, k, dnum)
+    }
+}
+
+pub trait LWESwitchingKeyPrepare<B: Backend>
+where
+    Self: GLWESwitchingKeyPrepare<B>,
 {
     fn lwe_switching_key_prepare_tmp_bytes<A>(&self, infos: &A)
     where
         A: GGLWEInfos,
     {
-        self.lwe_switching_key_prepare_tmp_bytes(infos);
+        self.glwe_switching_key_prepare_tmp_bytes(infos);
     }
-}
-
-impl<B: Backend> LWESwitchingKeyPrepared<Vec<u8>, B> {
-    pub fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A)
-    where
-        A: GLWEInfos,
-        Module<B>: LWESwitchingKeyPrepareTmpBytes,
-    {
-        module.glwe_secret_prepare_tmp_bytes(infos);
-    }
-}
-
-pub trait LWESwitchingKeyPrepare<B: Backend> {
-    fn lwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
-    where
-        R: LWESwitchingKeyPreparedToMut<B>,
-        O: LWESwitchingKeyToRef;
-}
-
-impl<B: Backend> LWESwitchingKeyPrepare<B> for Module<B>
-where
-    Module<B>: GLWESwitchingKeyPrepare<B>,
-{
-    fn lwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
+    fn lwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
     where
         R: LWESwitchingKeyPreparedToMut<B>,
         O: LWESwitchingKeyToRef,
     {
-        self.glwe_switching_prepare(&mut res.to_mut().0, other, scratch);
+        self.glwe_switching_prepare(&mut res.to_mut().0, &other.to_ref().0, scratch);
+    }
+}
+
+impl<B: Backend> LWESwitchingKeyPrepare<B> for Module<B> where Self: GLWESwitchingKeyPrepare<B> {}
+
+impl<B: Backend> LWESwitchingKeyPrepared<Vec<u8>, B> {
+    pub fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A)
+    where
+        A: GGLWEInfos,
+        Module<B>: LWESwitchingKeyPrepare<B>,
+    {
+        module.lwe_switching_key_prepare_tmp_bytes(infos);
     }
 }
 
 impl<D: DataMut, B: Backend> LWESwitchingKeyPrepared<D, B> {
-    fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &Scratch<B>)
+    fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &mut Scratch<B>)
     where
         O: LWESwitchingKeyToRef,
         Module<B>: LWESwitchingKeyPrepare<B>,
@@ -180,26 +184,6 @@ impl<D: DataMut, B: Backend> LWESwitchingKeyPrepared<D, B> {
     }
 }
 
-pub trait LWESwitchingKeyPrepareAlloc<B: Backend> {
-    fn lwe_switching_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: LWESwitchingKeyToRef;
-}
-
-impl<B: Backend> LWESwitchingKeyPrepareAlloc<B> for Module<B>
-where
-    Module<B>: LWESwitchingKeyPrepare<B>,
-{
-    fn lwe_switching_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: LWESwitchingKeyToRef,
-    {
-        let mut ct_prep: LWESwitchingKeyPrepared<Vec<u8>, B> = LWESwitchingKeyPrepared::alloc(self, &other.to_ref());
-        self.lwe_switching_key_prepare(&mut ct_prep, other, scratch);
-        ct_prep
-    }
-}
-
 pub trait LWESwitchingKeyPreparedToRef<B: Backend> {
     fn to_ref(&self) -> LWESwitchingKeyPrepared<&[u8], B>;
 }
diff --git a/poulpy-core/src/layouts/prepared/lwe_to_glwe_ksk.rs b/poulpy-core/src/layouts/prepared/lwe_to_glwe_ksk.rs
index 954553a..ed99a51 100644
--- a/poulpy-core/src/layouts/prepared/lwe_to_glwe_ksk.rs
+++ b/poulpy-core/src/layouts/prepared/lwe_to_glwe_ksk.rs
@@ -1,11 +1,11 @@
-use poulpy_hal::{
-    api::{VmpPMatAlloc, VmpPMatAllocBytes},
-    layouts::{Backend, Data, DataMut, DataRef, Module, Scratch},
-};
+use poulpy_hal::layouts::{Backend, Data, DataMut, DataRef, Module, Scratch};
 
 use crate::layouts::{
     Base2K, Degree, Dnum, Dsize, GGLWEInfos, GLWEInfos, LWEInfos, LWEToGLWESwitchingKeyToRef, Rank, TorusPrecision,
-    prepared::{GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedToMut, GLWESwitchingKeyPreparedToRef},
+    prepared::{
+        GLWESwitchingKeyPrepare, GLWESwitchingKeyPrepared, GLWESwitchingKeyPreparedAlloc, GLWESwitchingKeyPreparedToMut,
+        GLWESwitchingKeyPreparedToRef,
+    },
 };
 
 /// A special [GLWESwitchingKey] required to for the conversion from [LWECiphertext] to [GLWECiphertext].
@@ -54,11 +54,22 @@ impl<D: Data, B: Backend> GGLWEInfos for LWEToGLWESwitchingKeyPrepared<D, B> {
     }
 }
 
-impl<B: Backend> LWEToGLWESwitchingKeyPrepared<Vec<u8>, B> {
-    pub fn alloc<A>(module: &Module<B>, infos: &A) -> Self
+pub trait LWEToGLWESwitchingKeyPreparedAlloc<B: Backend>
+where
+    Self: GLWESwitchingKeyPreparedAlloc<B>,
+{
+    fn lwe_to_glwe_switching_key_prepared_alloc(
+        &self,
+        base2k: Base2K,
+        k: TorusPrecision,
+        rank_out: Rank,
+        dnum: Dnum,
+    ) -> LWEToGLWESwitchingKeyPrepared<Vec<u8>, B> {
+        LWEToGLWESwitchingKeyPrepared(self.glwe_switching_key_prepared_alloc(base2k, k, Rank(1), rank_out, dnum, Dsize(1)))
+    }
+    fn lwe_to_glwe_switching_key_prepared_alloc_from_infos<A>(&self, infos: &A) -> LWEToGLWESwitchingKeyPrepared<Vec<u8>, B>
     where
         A: GGLWEInfos,
-        Module<B>: VmpPMatAlloc<B>,
     {
         debug_assert_eq!(
             infos.rank_in().0,
@@ -70,28 +81,22 @@ impl<B: Backend> LWEToGLWESwitchingKeyPrepared<Vec<u8>, B> {
             1,
             "dsize > 1 is not supported for LWEToGLWESwitchingKey"
         );
-        Self(GLWESwitchingKeyPrepared::alloc_from_infos(module, infos))
+        self.lwe_to_glwe_switching_key_prepared_alloc(infos.base2k(), infos.k(), infos.rank_out(), infos.dnum())
     }
 
-    pub fn alloc_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank_out: Rank, dnum: Dnum) -> Self
-    where
-        Module<B>: VmpPMatAlloc<B>,
-    {
-        Self(GLWESwitchingKeyPrepared::alloc(
-            module,
-            base2k,
-            k,
-            Rank(1),
-            rank_out,
-            dnum,
-            Dsize(1),
-        ))
+    fn lwe_to_glwe_switching_key_prepared_alloc_bytes(
+        &self,
+        base2k: Base2K,
+        k: TorusPrecision,
+        rank_out: Rank,
+        dnum: Dnum,
+    ) -> usize {
+        self.glwe_switching_key_prepared_alloc_bytes(base2k, k, Rank(1), rank_out, dnum, Dsize(1))
     }
 
-    pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
+    fn lwe_to_glwe_switching_key_prepared_alloc_bytes_from_infos<A>(&self, infos: &A) -> usize
     where
         A: GGLWEInfos,
-        Module<B>: VmpPMatAllocBytes,
     {
         debug_assert_eq!(
             infos.rank_in().0,
@@ -103,67 +108,73 @@ impl<B: Backend> LWEToGLWESwitchingKeyPrepared<Vec<u8>, B> {
             1,
             "dsize > 1 is not supported for LWEToGLWESwitchingKey"
         );
-        GLWESwitchingKeyPrepared::alloc_bytes_from_infos(module, infos)
-    }
-
-    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum, rank_out: Rank) -> usize
-    where
-        Module<B>: VmpPMatAllocBytes,
-    {
-        GLWESwitchingKeyPrepared::alloc_bytes(module, base2k, k, Rank(1), rank_out, dnum, Dsize(1))
+        self.lwe_to_glwe_switching_key_prepared_alloc_bytes(infos.base2k(), infos.k(), infos.rank_out(), infos.dnum())
     }
 }
 
-pub trait LWEToGLWESwitchingKeyPrepareTmpBytes {
-    fn lwe_to_glwe_switching_key_prepare_tmp_bytes<A>(&self, infos: &A)
-    where
-        A: GGLWEInfos;
-}
+impl<B: Backend> LWEToGLWESwitchingKeyPreparedAlloc<B> for Module<B> where Self: GLWESwitchingKeyPreparedAlloc<B> {}
 
-impl<B: Backend> LWEToGLWESwitchingKeyPrepareTmpBytes for Module<B>
+impl<B: Backend> LWEToGLWESwitchingKeyPrepared<Vec<u8>, B>
 where
-    Module<B>: LWEToGLWESwitchingKeyPrepareTmpBytes,
+    Module<B>: LWEToGLWESwitchingKeyPreparedAlloc<B>,
+{
+    pub fn alloc_from_infos<A>(module: &Module<B>, infos: &A) -> Self
+    where
+        A: GGLWEInfos,
+    {
+        module.lwe_to_glwe_switching_key_prepared_alloc_from_infos(infos)
+    }
+
+    pub fn alloc(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank_out: Rank, dnum: Dnum) -> Self {
+        module.lwe_to_glwe_switching_key_prepared_alloc(base2k, k, rank_out, dnum)
+    }
+
+    pub fn alloc_bytes_from_infos<A>(module: &Module<B>, infos: &A) -> usize
+    where
+        A: GGLWEInfos,
+    {
+        module.lwe_to_glwe_switching_key_prepared_alloc_bytes_from_infos(infos)
+    }
+
+    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, rank_out: Rank, dnum: Dnum) -> usize {
+        module.lwe_to_glwe_switching_key_prepared_alloc_bytes(base2k, k, rank_out, dnum)
+    }
+}
+
+pub trait LWEToGLWESwitchingKeyPrepare<B: Backend>
+where
+    Self: GLWESwitchingKeyPrepare<B>,
 {
     fn lwe_to_glwe_switching_key_prepare_tmp_bytes<A>(&self, infos: &A)
     where
         A: GGLWEInfos,
     {
-        self.lwe_to_glwe_switching_key_prepare_tmp_bytes(infos);
+        self.glwe_switching_key_prepare_tmp_bytes(infos);
     }
-}
 
-impl<B: Backend> LWEToGLWESwitchingKeyPrepared<Vec<u8>, B> {
-    pub fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A)
-    where
-        A: GLWEInfos,
-        Module<B>: LWEToGLWESwitchingKeyPrepareTmpBytes,
-    {
-        module.glwe_secret_prepare_tmp_bytes(infos);
-    }
-}
-
-pub trait LWEToGLWESwitchingKeyPrepare<B: Backend> {
-    fn lwe_to_glwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
-    where
-        R: LWEToGLWESwitchingKeyPreparedToMut<B>,
-        O: LWEToGLWESwitchingKeyToRef;
-}
-
-impl<B: Backend> LWEToGLWESwitchingKeyPrepare<B> for Module<B>
-where
-    Module<B>: GLWESwitchingKeyPrepare<B>,
-{
-    fn lwe_to_glwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &Scratch<B>)
+    fn lwe_to_glwe_switching_key_prepare<R, O>(&self, res: &mut R, other: &O, scratch: &mut Scratch<B>)
     where
         R: LWEToGLWESwitchingKeyPreparedToMut<B>,
         O: LWEToGLWESwitchingKeyToRef,
     {
-        self.glwe_switching_prepare(&mut res.to_mut().0, other, scratch);
+        self.glwe_switching_prepare(&mut res.to_mut().0, &other.to_ref().0, scratch);
+    }
+}
+
+impl<B: Backend> LWEToGLWESwitchingKeyPrepare<B> for Module<B> where Self: GLWESwitchingKeyPrepare<B> {}
+
+impl<B: Backend> LWEToGLWESwitchingKeyPrepared<Vec<u8>, B> {
+    pub fn prepare_tmp_bytes<A>(&self, module: &Module<B>, infos: &A)
+    where
+        A: GGLWEInfos,
+        Module<B>: LWEToGLWESwitchingKeyPrepare<B>,
+    {
+        module.lwe_to_glwe_switching_key_prepare_tmp_bytes(infos);
     }
 }
 
 impl<D: DataMut, B: Backend> LWEToGLWESwitchingKeyPrepared<D, B> {
-    fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &Scratch<B>)
+    fn prepare<O>(&mut self, module: &Module<B>, other: &O, scratch: &mut Scratch<B>)
     where
         O: LWEToGLWESwitchingKeyToRef,
         Module<B>: LWEToGLWESwitchingKeyPrepare<B>,
@@ -172,26 +183,6 @@ impl<D: DataMut, B: Backend> LWEToGLWESwitchingKeyPrepared<D, B> {
     }
 }
 
-pub trait LWEToGLWESwitchingKeyPrepareAlloc<B: Backend> {
-    fn lwe_to_glwe_switching_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: LWEToGLWESwitchingKeyToRef;
-}
-
-impl<B: Backend> LWEToGLWESwitchingKeyPrepareAlloc<B> for Module<B>
-where
-    Module<B>: LWEToGLWESwitchingKeyPrepare<B>,
-{
-    fn lwe_to_glwe_switching_key_prepare_alloc<O>(&self, other: &O, scratch: &mut Scratch<B>)
-    where
-        O: LWEToGLWESwitchingKeyToRef,
-    {
-        let mut ct_prep: LWEToGLWESwitchingKeyPrepared<Vec<u8>, B> = LWEToGLWESwitchingKeyPrepared::alloc(self, &other.to_ref());
-        self.lwe_to_glwe_switching_key_prepare(&mut ct_prep, other, scratch);
-        ct_prep
-    }
-}
-
 pub trait LWEToGLWESwitchingKeyPreparedToRef<B: Backend> {
     fn to_ref(&self) -> LWEToGLWESwitchingKeyPrepared<&[u8], B>;
 }
diff --git a/poulpy-core/src/scratch.rs b/poulpy-core/src/scratch.rs
index 0a94b39..01b260e 100644
--- a/poulpy-core/src/scratch.rs
+++ b/poulpy-core/src/scratch.rs
@@ -129,12 +129,11 @@ where
     {
         let (data, scratch) = self.take_vec_znx(infos.n().into(), (infos.rank() + 1).into(), infos.size());
         (
-            GLWECiphertext::builder()
-                .base2k(infos.base2k())
-                .k(infos.k())
-                .data(data)
-                .build()
-                .unwrap(),
+            GLWECiphertext {
+                k: infos.k(),
+                base2k: infos.base2k(),
+                data,
+            },
             scratch,
         )
     }
@@ -169,12 +168,11 @@ where
     {
         let (data, scratch) = self.take_vec_znx(infos.n().into(), 1, infos.size());
         (
-            GLWEPlaintext::builder()
-                .base2k(infos.base2k())
-                .k(infos.k())
-                .data(data)
-                .build()
-                .unwrap(),
+            GLWEPlaintext {
+                k: infos.k(),
+                base2k: infos.base2k(),
+                data,
+            },
             scratch,
         )
     }
@@ -196,13 +194,12 @@ where
             infos.size(),
         );
         (
-            GGLWE::builder()
-                .base2k(infos.base2k())
-                .k(infos.k())
-                .dsize(infos.dsize())
-                .data(data)
-                .build()
-                .unwrap(),
+            GGLWE {
+                k: infos.k(),
+                base2k: infos.base2k(),
+                dsize: infos.dsize(),
+                data,
+            },
             scratch,
         )
     }
@@ -224,13 +221,12 @@ where
             infos.size(),
         );
         (
-            GGLWEPrepared::builder()
-                .base2k(infos.base2k())
-                .dsize(infos.dsize())
-                .k(infos.k())
-                .data(data)
-                .build()
-                .unwrap(),
+            GGLWEPrepared {
+                k: infos.k(),
+                base2k: infos.base2k(),
+                dsize: infos.dsize(),
+                data,
+            },
             scratch,
         )
     }
@@ -252,13 +248,12 @@ where
             infos.size(),
         );
         (
-            GGSW::builder()
-                .base2k(infos.base2k())
-                .dsize(infos.dsize())
-                .k(infos.k())
-                .data(data)
-                .build()
-                .unwrap(),
+            GGSW {
+                k: infos.k(),
+                base2k: infos.base2k(),
+                dsize: infos.dsize(),
+                data,
+            },
             scratch,
         )
     }
@@ -280,13 +275,12 @@ where
             infos.size(),
         );
         (
-            GGSWPrepared::builder()
-                .base2k(infos.base2k())
-                .dsize(infos.dsize())
-                .k(infos.k())
-                .data(data)
-                .build()
-                .unwrap(),
+            GGSWPrepared {
+                k: infos.k(),
+                base2k: infos.base2k(),
+                dsize: infos.dsize(),
+                data,
+            },
             scratch,
         )
     }
@@ -321,13 +315,12 @@ where
     {
         let (data, scratch) = self.take_vec_znx(infos.n().into(), (infos.rank() + 1).into(), infos.size());
         (
-            GLWEPublicKey::builder()
-                .base2k(infos.base2k())
-                .k(infos.k())
-                .base2k(infos.base2k())
-                .data(data)
-                .build()
-                .unwrap(),
+            GLWEPublicKey {
+                k: infos.k(),
+                dist: Distribution::NONE,
+                base2k: infos.base2k(),
+                data,
+            },
             scratch,
         )
     }
@@ -343,12 +336,12 @@ where
     {
         let (data, scratch) = self.take_vec_znx_dft(infos.n().into(), (infos.rank() + 1).into(), infos.size());
         (
-            GLWEPublicKeyPrepared::builder()
-                .base2k(infos.base2k())
-                .k(infos.k())
-                .data(data)
-                .build()
-                .unwrap(),
+            GLWEPublicKeyPrepared {
+                k: infos.k(),
+                dist: Distribution::NONE,
+                base2k: infos.base2k(),
+                data,
+            },
             scratch,
         )
     }
diff --git a/poulpy-core/src/tests/test_suite/automorphism/ggsw_ct.rs b/poulpy-core/src/tests/test_suite/automorphism/ggsw_ct.rs
index 5b066a1..b63d616 100644
--- a/poulpy-core/src/tests/test_suite/automorphism/ggsw_ct.rs
+++ b/poulpy-core/src/tests/test_suite/automorphism/ggsw_ct.rs
@@ -182,7 +182,7 @@ where
                 AutomorphismKeyPrepared::alloc_from_infos(module, &auto_key_layout);
             auto_key_prepared.prepare(module, &auto_key, scratch.borrow());
 
-            let mut tsk_prepared: TensorKeyPrepared<Vec<u8>, B> = TensorKeyPrepared::alloc(module, &tensor_key_layout);
+            let mut tsk_prepared: TensorKeyPrepared<Vec<u8>, B> = TensorKeyPrepared::alloc_from_infos(module, &tensor_key_layout);
             tsk_prepared.prepare(module, &tensor_key, scratch.borrow());
 
             ct_out.automorphism(
@@ -362,7 +362,7 @@ where
                 AutomorphismKeyPrepared::alloc_from_infos(module, &auto_key_layout);
             auto_key_prepared.prepare(module, &auto_key, scratch.borrow());
 
-            let mut tsk_prepared: TensorKeyPrepared<Vec<u8>, B> = TensorKeyPrepared::alloc(module, &tensor_key_layout);
+            let mut tsk_prepared: TensorKeyPrepared<Vec<u8>, B> = TensorKeyPrepared::alloc_from_infos(module, &tensor_key_layout);
             tsk_prepared.prepare(module, &tensor_key, scratch.borrow());
 
             ct.automorphism_inplace(module, &auto_key_prepared, &tsk_prepared, scratch.borrow());
diff --git a/poulpy-schemes/src/tfhe/bdd_arithmetic/ciphertexts/block_prepared.rs b/poulpy-schemes/src/tfhe/bdd_arithmetic/ciphertexts/block_prepared.rs
index 3213894..1af36d1 100644
--- a/poulpy-schemes/src/tfhe/bdd_arithmetic/ciphertexts/block_prepared.rs
+++ b/poulpy-schemes/src/tfhe/bdd_arithmetic/ciphertexts/block_prepared.rs
@@ -101,7 +101,7 @@ where
     {
         Self {
             blocks: (0..T::WORD_SIZE)
-                .map(|_| GGSWPrepared::alloc_with(module, base2k, k, dnum, dsize, rank))
+                .map(|_| GGSWPrepared::alloc(module, base2k, k, dnum, dsize, rank))
                 .collect(),
             _base: 1,
             _phantom: PhantomData,
diff --git a/poulpy-schemes/src/tfhe/blind_rotation/cggi_key.rs b/poulpy-schemes/src/tfhe/blind_rotation/cggi_key.rs
index a8fa39a..22e9bd4 100644
--- a/poulpy-schemes/src/tfhe/blind_rotation/cggi_key.rs
+++ b/poulpy-schemes/src/tfhe/blind_rotation/cggi_key.rs
@@ -122,7 +122,7 @@ where
         A: BlindRotationKeyInfos,
     {
         let mut data: Vec<GGSWPrepared<Vec<u8>, B>> = Vec::with_capacity(infos.n_lwe().into());
-        (0..infos.n_lwe().as_usize()).for_each(|_| data.push(GGSWPrepared::alloc(module, infos)));
+        (0..infos.n_lwe().as_usize()).for_each(|_| data.push(GGSWPrepared::alloc_from_infos(module, infos)));
         Self {
             data,
             dist: Distribution::NONE,