@@ -1,16 +1,16 @@
 use poulpy_hal::{
     api::{
-        ModuleN, ScratchTakeBasic, VecZnxBigNormalize, VecZnxBigNormalizeTmpBytes, VecZnxDftApply, VecZnxDftBytesOf,
-        VecZnxIdftApplyConsume, VecZnxNormalize, VecZnxNormalizeTmpBytes, VmpApplyDftToDft, VmpApplyDftToDftAdd,
-        VmpApplyDftToDftTmpBytes,
+        ModuleN, ScratchTakeBasic, VecZnxBigAddSmallInplace, VecZnxBigNormalize, VecZnxBigNormalizeTmpBytes, VecZnxDftApply,
+        VecZnxDftBytesOf, VecZnxIdftApplyConsume, VecZnxNormalize, VecZnxNormalizeTmpBytes, VmpApplyDftToDft,
+        VmpApplyDftToDftAdd, VmpApplyDftToDftTmpBytes,
     },
     layouts::{Backend, DataMut, DataViewMut, Module, Scratch, VecZnx, VecZnxBig, VecZnxDft},
 };
 
 use crate::{
-    ScratchTakeCore,
+    GLWENormalize, ScratchTakeCore,
     layouts::{
-        GGSWInfos, GLWE, GLWEInfos, GLWEToMut, GLWEToRef, LWEInfos,
+        GGSWInfos, GLWE, GLWEInfos, GLWELayout, GLWEToMut, GLWEToRef, LWEInfos,
         prepared::{GGSWPrepared, GGSWPreparedToRef},
     },
 };
@@ -67,11 +67,22 @@ R: GLWEToMut,
         A: GLWEToRef,
         D: GGSWPreparedToRef<BE> + GGSWInfos,
         Scratch<BE>: ScratchTakeCore<BE>;
+    fn glwe_external_product_add<R, A, D>(&self, res: &mut R, lhs: &A, rhs: &D, scratch: &mut Scratch<BE>)
+    where
+        R: GLWEToMut,
+        A: GLWEToRef,
+        D: GGSWPreparedToRef<BE> + GGSWInfos,
+        Scratch<BE>: ScratchTakeCore<BE>;
 }
 
 impl<BE: Backend> GLWEExternalProduct<BE> for Module<BE>
 where
-    Self: GLWEExternalProductInternal<BE> + VecZnxDftBytesOf + VecZnxBigNormalize<BE> + VecZnxBigNormalizeTmpBytes,
+    Self: GLWEExternalProductInternal<BE>
+        + VecZnxDftBytesOf
+        + VecZnxBigNormalize<BE>
+        + VecZnxBigNormalizeTmpBytes
+        + VecZnxBigAddSmallInplace<BE>
+        + GLWENormalize<BE>,
 {
     fn glwe_external_product_tmp_bytes<R, A, B>(&self, res_infos: &R, a_infos: &A, b_infos: &B) -> usize
     where
@@ -161,6 +172,80 @@ &res_big,
                 j,
                 scratch_1,
             );
+        }
+    }
+
+    fn glwe_external_product_add<R, A, D>(&self, res: &mut R, a: &A, key: &D, scratch: &mut Scratch<BE>)
+    where
+        R: GLWEToMut,
+        A: GLWEToRef,
+        D: GGSWPreparedToRef<BE>,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        let res: &mut GLWE<&mut [u8]> = &mut res.to_mut();
+        let a: &GLWE<&[u8]> = &a.to_ref();
+        let key: &GGSWPrepared<&[u8], BE> = &key.to_ref();
+
+        assert_eq!(a.base2k(), res.base2k());
+
+        let res_base2k: usize = res.base2k().into();
+        let key_base2k: usize = key.base2k().into();
+
+        #[cfg(debug_assertions)]
+        {
+            use poulpy_hal::api::ScratchAvailable;
+
+            assert_eq!(key.rank(), a.rank());
+            assert_eq!(key.rank(), res.rank());
+            assert_eq!(key.n(), res.n());
+            assert_eq!(a.n(), res.n());
+            assert!(scratch.available() >= self.glwe_external_product_tmp_bytes(res, a, key));
+        }
+
+        if res_base2k == key_base2k {
+            let (res_dft, scratch_1) = scratch.take_vec_znx_dft(self, (res.rank() + 1).into(), key.size()); // Todo optimise
+            let mut res_big = self.glwe_external_product_internal(res_dft, a, key, scratch_1);
+            for j in 0..(res.rank() + 1).into() {
+                self.vec_znx_big_add_small_inplace(&mut res_big, j, res.data(), j);
+                self.vec_znx_big_normalize(
+                    res_base2k,
+                    &mut res.data,
+                    j,
+                    key_base2k,
+                    &res_big,
+                    j,
+                    scratch_1,
+                );
+            }
+        } else {
+            let (mut a_conv, scratch_1) = scratch.take_glwe(&GLWELayout {
+                n: a.n(),
+                base2k: key.base2k(),
+                k: a.k(),
+                rank: a.rank(),
+            });
+            let (mut res_conv, scratch_2) = scratch_1.take_glwe(&GLWELayout {
+                n: res.n(),
+                base2k: key.base2k(),
+                k: res.k(),
+                rank: res.rank(),
+            });
+            self.glwe_normalize(&mut a_conv, a, scratch_2);
+            self.glwe_normalize(&mut res_conv, res, scratch_2);
+            let (res_dft, scratch_2) = scratch_2.take_vec_znx_dft(self, (res.rank() + 1).into(), key.size()); // Todo optimise
+            let mut res_big = self.glwe_external_product_internal(res_dft, &a_conv, key, scratch_2);
+            for j in 0..(res.rank() + 1).into() {
+                self.vec_znx_big_add_small_inplace(&mut res_big, j, res_conv.data(), j);
+                self.vec_znx_big_normalize(
+                    res_base2k,
+                    &mut res.data,
+                    j,
+                    key_base2k,
+                    &res_big,
+                    j,
+                    scratch_2,
+                );
+            }
         }
     }
 }

@@ -7,7 +7,7 @@ };
 
 use crate::{
     GLWEAdd, GLWEAutomorphism, GLWECopy, GLWENormalize, GLWERotate, GLWEShift, GLWESub, GLWETrace, ScratchTakeCore,
-    layouts::{GGLWEInfos, GGLWEPreparedToRef, GLWEAutomorphismKeyHelper, GLWEInfos, GLWEToMut, GLWEToRef, GetGaloisElement},
+    layouts::{GGLWEInfos, GGLWEPreparedToRef, GLWEAutomorphismKeyHelper, GLWEInfos, GLWEToMut, GetGaloisElement},
 };
 pub trait GLWEPacking<BE: Backend> {
     /// Packs [x_0: GLWE(m_0), x_1: GLWE(m_1), ..., x_i: GLWE(m_i)]
@@ -21,7 +21,7 @@ keys: &H,
         scratch: &mut Scratch<BE>,
     ) where
         R: GLWEToMut + GLWEInfos,
-        A: GLWEToMut + GLWEToRef + GLWEInfos,
+        A: GLWEToMut + GLWEInfos,
         K: GGLWEPreparedToRef<BE> + GetGaloisElement + GGLWEInfos,
         H: GLWEAutomorphismKeyHelper<K, BE>;
 }
@@ -51,7 +51,7 @@ keys: &H,
         scratch: &mut Scratch<BE>,
     ) where
         R: GLWEToMut + GLWEInfos,
-        A: GLWEToMut + GLWEToRef + GLWEInfos,
+        A: GLWEToMut + GLWEInfos,
         K: GGLWEPreparedToRef<BE> + GetGaloisElement + GGLWEInfos,
         H: GLWEAutomorphismKeyHelper<K, BE>,
     {
@@ -97,8 +97,8 @@ auto_key: &K,
     scratch: &mut Scratch<BE>,
 ) where
     M: GLWEAutomorphism<BE> + GLWERotate<BE> + GLWESub + GLWEShift<BE> + GLWEAdd + GLWENormalize<BE>,
-    A: GLWEToMut + GLWEToRef + GLWEInfos,
-    B: GLWEToMut + GLWEToRef + GLWEInfos,
+    A: GLWEToMut + GLWEInfos,
+    B: GLWEToMut + GLWEInfos,
     K: GGLWEPreparedToRef<BE> + GetGaloisElement + GGLWEInfos,
     Scratch<BE>: ScratchTakeCore<BE>,
 {

@@ -189,7 +189,7 @@ self.data.write_to(writer)
     }
 }
 
-pub trait GLWEToRef {
+pub trait GLWEToRef: Sized {
     fn to_ref(&self) -> GLWE<&[u8]>;
 }
 
@@ -203,14 +203,11 @@ }
     }
 }
 
-pub trait GLWEToMut {
+pub trait GLWEToMut: GLWEToRef {
     fn to_mut(&mut self) -> GLWE<&mut [u8]>;
 }
 
-impl<D: DataMut> GLWEToMut for GLWE<D>
-where
-    Self: GLWEToRef,
-{
+impl<D: DataMut> GLWEToMut for GLWE<D> {
     fn to_mut(&mut self) -> GLWE<&mut [u8]> {
         GLWE {
             k: self.k,

@@ -402,6 +402,84 @@ fn glwe_normalize_tmp_bytes(&self) -> usize {
         self.vec_znx_normalize_tmp_bytes()
     }
 
+    /// Usage:
+    /// let mut tmp_b: Option<GLWE<&mut [u8]>> = None;
+    /// let (b_conv, scratch_1) = glwe_maybe_convert_in_place(self, b, res.base2k().as_u32(), &mut tmp_b, scratch);
+    fn glwe_maybe_cross_normalize_to_ref<'a, A>(
+        &self,
+        glwe: &'a A,
+        target_base2k: usize,
+        tmp_slot: &'a mut Option<GLWE<&'a mut [u8]>>, // caller-owned scratch-backed temp
+        scratch: &'a mut Scratch<BE>,
+    ) -> (GLWE<&'a [u8]>, &'a mut Scratch<BE>)
+    where
+        A: GLWEToRef + GLWEInfos,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        // No conversion: just use the original GLWE
+        if glwe.base2k().as_usize() == target_base2k {
+            // Drop any previous temp; it's stale for this base
+            tmp_slot.take();
+            return (glwe.to_ref(), scratch);
+        }
+
+        // Conversion: allocate a temporary GLWE in scratch
+        let mut layout = glwe.glwe_layout();
+        layout.base2k = target_base2k.into();
+
+        let (tmp, scratch2) = scratch.take_glwe(&layout);
+        *tmp_slot = Some(tmp);
+
+        // Get a mutable handle to the temp and normalize into it
+        let tmp_ref: &mut GLWE<&mut [u8]> = tmp_slot
+            .as_mut()
+            .expect("tmp_slot just set to Some, but found None");
+
+        self.glwe_normalize(tmp_ref, glwe, scratch2);
+
+        // Return a trait-object view of the temp
+        (tmp_ref.to_ref(), scratch2)
+    }
+
+    /// Usage:
+    /// let mut tmp_b: Option<GLWE<&mut [u8]>> = None;
+    /// let (b_conv, scratch_1) = glwe_maybe_convert_in_place(self, b, res.base2k().as_u32(), &mut tmp_b, scratch);
+    fn glwe_maybe_cross_normalize_to_mut<'a, A>(
+        &self,
+        glwe: &'a mut A,
+        target_base2k: usize,
+        tmp_slot: &'a mut Option<GLWE<&'a mut [u8]>>, // caller-owned scratch-backed temp
+        scratch: &'a mut Scratch<BE>,
+    ) -> (GLWE<&'a mut [u8]>, &'a mut Scratch<BE>)
+    where
+        A: GLWEToMut + GLWEInfos,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        // No conversion: just use the original GLWE
+        if glwe.base2k().as_usize() == target_base2k {
+            // Drop any previous temp; it's stale for this base
+            tmp_slot.take();
+            return (glwe.to_mut(), scratch);
+        }
+
+        // Conversion: allocate a temporary GLWE in scratch
+        let mut layout = glwe.glwe_layout();
+        layout.base2k = target_base2k.into();
+
+        let (tmp, scratch2) = scratch.take_glwe(&layout);
+        *tmp_slot = Some(tmp);
+
+        // Get a mutable handle to the temp and normalize into it
+        let tmp_ref: &mut GLWE<&mut [u8]> = tmp_slot
+            .as_mut()
+            .expect("tmp_slot just set to Some, but found None");
+
+        self.glwe_normalize(tmp_ref, glwe, scratch2);
+
+        // Return a trait-object view of the temp
+        (tmp_ref.to_mut(), scratch2)
+    }
+
     fn glwe_normalize<R, A>(&self, res: &mut R, a: &A, scratch: &mut Scratch<BE>)
     where
         R: GLWEToMut,

@@ -0,0 +1,221 @@
+use itertools::Itertools;
+use poulpy_core::{
+    GLWECopy, ScratchTakeCore,
+    layouts::{GGSWInfos, GGSWPrepared, GLWE, GLWEInfos, GLWEToMut, GLWEToRef},
+};
+use poulpy_hal::layouts::{Backend, Module, Scratch};
+
+use crate::tfhe::bdd_arithmetic::{Cmux, Cswap, GetGGSWBit};
+
+pub struct GLWEBlindRetriever {
+    accumulators: Vec<Accumulator>,
+    counter: usize,
+}
+
+impl GLWEBlindRetriever {
+    pub fn alloc<A>(infos: &A, size: usize) -> Self
+    where
+        A: GLWEInfos,
+    {
+        let log2_max_address: usize = (u32::BITS - (size as u32 - 1).leading_zeros()) as usize;
+        Self {
+            accumulators: (0..log2_max_address)
+                .map(|_| Accumulator::alloc(infos))
+                .collect_vec(),
+            counter: 0,
+        }
+    }
+
+    pub fn retrieve<M, R, A, S, BE: Backend>(
+        &mut self,
+        module: &M,
+        res: &mut R,
+        data: &[A],
+        selector: &S,
+        scratch: &mut Scratch<BE>,
+    ) where
+        M: GLWECopy + Cmux<BE>,
+        R: GLWEToMut,
+        A: GLWEToRef,
+        S: GetGGSWBit<BE>,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        self.reset();
+
+        for ct in data {
+            self.add(module, ct, selector, scratch);
+        }
+        self.flush(module, res, selector, scratch);
+    }
+
+    pub fn add<A, S, M, BE: Backend>(&mut self, module: &M, a: &A, selector: &S, scratch: &mut Scratch<BE>)
+    where
+        A: GLWEToRef,
+        S: GetGGSWBit<BE>,
+        M: GLWECopy + Cmux<BE>,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        assert!(
+            (self.counter as u32) < 1 << self.accumulators.len(),
+            "Accumulating limit of {} reached",
+            1 << self.accumulators.len()
+        );
+
+        add_core(module, a, &mut self.accumulators, 0, selector, scratch);
+        self.counter += 1;
+    }
+
+    pub fn flush<R, M, S, BE: Backend>(&mut self, module: &M, res: &mut R, selector: &S, scratch: &mut Scratch<BE>)
+    where
+        R: GLWEToMut,
+        S: GetGGSWBit<BE>,
+        M: GLWECopy + Cmux<BE>,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        for i in 0..self.accumulators.len() - 1 {
+            let (acc_prev, acc_next) = self.accumulators.split_at_mut(i + 1);
+            if acc_prev[i].num != 0 {
+                add_core(
+                    module,
+                    &acc_prev[i].data,
+                    acc_next,
+                    i + 1,
+                    selector,
+                    scratch,
+                );
+                acc_prev[0].num = 0
+            }
+        }
+        module.glwe_copy(res, &self.accumulators.last().unwrap().data);
+        self.reset()
+    }
+
+    fn reset(&mut self) {
+        for acc in self.accumulators.iter_mut() {
+            acc.num = 0;
+        }
+    }
+}
+
+struct Accumulator {
+    data: GLWE<Vec<u8>>,
+    num: usize, // Number of accumulated values
+}
+
+impl Accumulator {
+    pub fn alloc<A>(infos: &A) -> Self
+    where
+        A: GLWEInfos,
+    {
+        Self {
+            data: GLWE::alloc_from_infos(infos),
+            num: 0,
+        }
+    }
+}
+
+fn add_core<A, S, M, BE: Backend>(
+    module: &M,
+    a: &A,
+    accumulators: &mut [Accumulator],
+    i: usize,
+    selector: &S,
+    scratch: &mut Scratch<BE>,
+) where
+    A: GLWEToRef,
+    S: GetGGSWBit<BE>,
+    M: GLWECopy + Cmux<BE>,
+    Scratch<BE>: ScratchTakeCore<BE>,
+{
+    // Isolate the first accumulator
+    let (acc_prev, acc_next) = accumulators.split_at_mut(1);
+
+    match acc_prev[0].num {
+        0 => {
+            module.glwe_copy(&mut acc_prev[0].data, a);
+            acc_prev[0].num = 1;
+        }
+        1 => {
+            module.cmux_inplace_neg(&mut acc_prev[0].data, a, &selector.get_bit(i), scratch);
+
+            if !acc_next.is_empty() {
+                add_core(
+                    module,
+                    &acc_prev[0].data,
+                    acc_next,
+                    i + 1,
+                    selector,
+                    scratch,
+                );
+            }
+
+            acc_prev[0].num = 0
+        }
+        _ => {
+            panic!("something went wrong")
+        }
+    }
+}
+
+impl<BE: Backend> GLWEBlindRetrieval<BE> for Module<BE> where Self: GLWECopy + Cmux<BE> + Cswap<BE> {}
+
+pub trait GLWEBlindRetrieval<BE: Backend>
+where
+    Self: GLWECopy + Cmux<BE> + Cswap<BE>,
+{
+    fn glwe_blind_retrieval_tmp_bytes<R, K>(&self, res_infos: &R, k_infos: &K) -> usize
+    where
+        R: GLWEInfos,
+        K: GGSWInfos,
+    {
+        self.cswap_tmp_bytes(res_infos, res_infos, k_infos)
+    }
+
+    fn glwe_blind_retrieval_statefull<R, K>(
+        &self,
+        res: &mut Vec<R>,
+        bits: &K,
+        bit_rsh: usize,
+        bit_mask: usize,
+        scratch: &mut Scratch<BE>,
+    ) where
+        R: GLWEToMut + GLWEInfos,
+        K: GetGGSWBit<BE>,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        for i in 0..bit_mask {
+            let t: usize = 1 << (bit_mask - i - 1);
+            let bit: &GGSWPrepared<&[u8], BE> = &bits.get_bit(bit_rsh + bit_mask - i - 1); // MSB -> LSB traversal
+            for j in 0..t {
+                if j + t < res.len() {
+                    let (lo, hi) = res.split_at_mut(j + t);
+                    self.cswap(&mut lo[j], &mut hi[0], bit, scratch);
+                }
+            }
+        }
+    }
+
+    fn glwe_blind_retrieval_statefull_rev<R, K>(
+        &self,
+        res: &mut Vec<R>,
+        bits: &K,
+        bit_rsh: usize,
+        bit_mask: usize,
+        scratch: &mut Scratch<BE>,
+    ) where
+        R: GLWEToMut + GLWEInfos,
+        K: GetGGSWBit<BE>,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        for i in (0..bit_mask).rev() {
+            let t: usize = 1 << (bit_mask - i - 1);
+            let bit: &GGSWPrepared<&[u8], BE> = &bits.get_bit(bit_rsh + bit_mask - i - 1); // MSB -> LSB traversal
+            for j in 0..t {
+                if j < res.len() && j + t < res.len() {
+                    let (lo, hi) = res.split_at_mut(j + t);
+                    self.cswap(&mut lo[j], &mut hi[0], bit, scratch);
+                }
+            }
+        }
+    }
+}

@@ -2,7 +2,7 @@ use std::collections::HashMap;
 
 use poulpy_core::{
     GLWECopy, GLWEDecrypt, ScratchTakeCore,
-    layouts::{GGSWInfos, GGSWPrepared, GLWE, GLWEInfos, GLWEToMut, GLWEToRef},
+    layouts::{GGSWInfos, GGSWPrepared, GLWE, GLWEInfos, GLWEToMut},
 };
 use poulpy_hal::layouts::{Backend, Module, Scratch, ZnxZero};
 
@@ -33,7 +33,7 @@ bit_mask: usize,
         scratch: &mut Scratch<BE>,
     ) where
         R: GLWEToMut,
-        A: GLWEToMut + GLWEToRef,
+        A: GLWEToMut,
         K: GetGGSWBit<BE>,
         Scratch<BE>: ScratchTakeCore<BE>,
     {

@@ -49,6 +49,18 @@ }
     }
 }
 
+impl<'a, T: UnsignedInteger> FheUint<&'a [u8], T> {
+    pub fn from_glwe_to_ref<G>(glwe: &'a G) -> Self
+    where
+        G: GLWEToRef,
+    {
+        FheUint {
+            bits: glwe.to_ref(),
+            _phantom: PhantomData,
+        }
+    }
+}
+
 impl<D: DataRef, T: UnsignedInteger> LWEInfos for FheUint<D, T> {
     fn base2k(&self) -> poulpy_core::layouts::Base2K {
         self.bits.base2k()
@@ -180,7 +192,7 @@ impl<D: DataMut, T: UnsignedInteger> FheUint<D, T> {
     /// Packs Vec<GLWE(bit[i])> into [FheUint].
     pub fn pack<G, M, K, H, BE: Backend>(&mut self, module: &M, mut bits: Vec<G>, keys: &H, scratch: &mut Scratch<BE>)
     where
-        G: GLWEToMut + GLWEToRef + GLWEInfos,
+        G: GLWEToMut + GLWEInfos,
         M: ModuleLogN + GLWEPacking<BE> + GLWECopy,
         K: GGLWEPreparedToRef<BE> + GetGaloisElement + GGLWEInfos,
         H: GLWEAutomorphismKeyHelper<K, BE>,

@@ -4,14 +4,16 @@
 use itertools::Itertools;
 use poulpy_core::{
     GLWECopy, GLWEExternalProductInternal, GLWENormalize, GLWESub, ScratchTakeCore,
-    layouts::{GGSWInfos, GGSWPrepared, GLWE, GLWEInfos, GLWEToMut, GLWEToRef, LWEInfos, prepared::GGSWPreparedToRef},
+    layouts::{
+        GGSWInfos, GGSWPrepared, GLWE, GLWEInfos, GLWELayout, GLWEToMut, GLWEToRef, LWEInfos, prepared::GGSWPreparedToRef,
+    },
 };
 use poulpy_hal::{
     api::{
-        ScratchAvailable, ScratchTakeBasic, VecZnxBigAddSmallInplace, VecZnxBigNormalize, VecZnxBigNormalizeTmpBytes,
-        VecZnxDftBytesOf,
+        ScratchAvailable, ScratchTakeBasic, VecZnxBigAddSmall, VecZnxBigAddSmallInplace, VecZnxBigBytesOf, VecZnxBigNormalize,
+        VecZnxBigNormalizeTmpBytes, VecZnxBigSubSmallA, VecZnxDftBytesOf,
     },
-    layouts::{Backend, DataMut, Module, Scratch, VecZnxBig, ZnxZero},
+    layouts::{Backend, DataMut, Module, Scratch, VecZnxBig, ZnxInfos, ZnxZero},
 };
 
 use crate::tfhe::bdd_arithmetic::GetGGSWBit;
@@ -260,6 +262,204 @@ Copy,
     None,
 }
 
+impl<BE: Backend> Cswap<BE> for Module<BE> where
+    Self: Sized
+        + GLWEExternalProductInternal<BE>
+        + GLWESub
+        + VecZnxBigAddSmallInplace<BE>
+        + GLWENormalize<BE>
+        + VecZnxDftBytesOf
+        + VecZnxBigNormalize<BE>
+        + VecZnxBigNormalizeTmpBytes
+        + GLWENormalize<BE>
+        + VecZnxBigAddSmall<BE>
+        + VecZnxBigSubSmallA<BE>
+        + VecZnxBigBytesOf
+{
+}
+
+pub trait Cswap<BE: Backend>
+where
+    Self: Sized
+        + GLWEExternalProductInternal<BE>
+        + GLWESub
+        + GLWECopy
+        + VecZnxBigAddSmallInplace<BE>
+        + GLWENormalize<BE>
+        + VecZnxDftBytesOf
+        + VecZnxBigNormalize<BE>
+        + VecZnxBigNormalizeTmpBytes
+        + GLWENormalize<BE>
+        + VecZnxBigAddSmall<BE>
+        + VecZnxBigSubSmallA<BE>
+        + VecZnxBigBytesOf,
+{
+    fn cswap_tmp_bytes<R, A, S>(&self, res_a_infos: &R, res_b_infos: &A, s_infos: &S) -> usize
+    where
+        R: GLWEInfos,
+        A: GLWEInfos,
+        S: GGSWInfos,
+    {
+        let res_dft: usize = self.bytes_of_vec_znx_dft((s_infos.rank() + 1).into(), s_infos.size());
+        let mut tot = res_dft
+            + (self.glwe_external_product_internal_tmp_bytes(res_a_infos, res_b_infos, s_infos)
+                + GLWE::bytes_of_from_infos(&GLWELayout {
+                    n: s_infos.n(),
+                    base2k: s_infos.base2k(),
+                    k: res_a_infos.k().max(res_b_infos.k()),
+                    rank: s_infos.rank(),
+                }))
+            .max(self.vec_znx_big_normalize_tmp_bytes());
+
+        if res_a_infos.base2k() != s_infos.base2k() {
+            tot += GLWE::bytes_of_from_infos(&GLWELayout {
+                n: res_a_infos.n(),
+                base2k: s_infos.base2k(),
+                k: res_a_infos.k(),
+                rank: res_a_infos.rank(),
+            });
+
+            tot += GLWE::bytes_of_from_infos(&GLWELayout {
+                n: res_b_infos.n(),
+                base2k: s_infos.base2k(),
+                k: res_b_infos.k(),
+                rank: res_b_infos.rank(),
+            });
+        }
+
+        tot += self.bytes_of_vec_znx_big(1, s_infos.size());
+
+        tot
+    }
+
+    fn cswap<A, B, S>(&self, res_a: &mut A, res_b: &mut B, s: &S, scratch: &mut Scratch<BE>)
+    where
+        A: GLWEToMut,
+        B: GLWEToMut,
+        S: GGSWPreparedToRef<BE> + GGSWInfos,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        let res_a: &mut GLWE<&mut [u8]> = &mut res_a.to_mut();
+        let res_b: &mut GLWE<&mut [u8]> = &mut res_b.to_mut();
+        let s: &GGSWPrepared<&[u8], BE> = &s.to_ref();
+        assert_eq!(res_a.base2k(), res_b.base2k());
+
+        let res_base2k: usize = res_a.base2k().as_usize();
+        let s_base2k: usize = s.base2k().as_usize();
+
+        if res_base2k == s_base2k {
+            let res_big: VecZnxBig<&mut [u8], BE>;
+            let (res_dft, scratch_1) = scratch.take_vec_znx_dft(self, (s.rank() + 1).into(), s.size()); // Todo optimise
+            {
+                // Temporary value storing a - b
+                let tmp_c_infos: GLWELayout = GLWELayout {
+                    n: s.n(),
+                    base2k: s.base2k(),
+                    k: res_a.k().max(res_b.k()),
+                    rank: s.rank(),
+                };
+                let (mut tmp_c, scratch_2) = scratch_1.take_glwe(&tmp_c_infos);
+                self.glwe_sub(&mut tmp_c, res_b, res_a);
+                res_big = self.glwe_external_product_internal(res_dft, &tmp_c, s, scratch_2);
+            }
+
+            // Single column res_big to store temporary value before normalization
+            let (mut res_big_tmp, scratch_2) = scratch_1.take_vec_znx_big::<_, BE>(self, 1, res_big.size());
+
+            // res_a = (b-a) * bit + a
+            for j in 0..(res_a.rank() + 1).into() {
+                self.vec_znx_big_add_small(&mut res_big_tmp, 0, &res_big, j, res_a.data(), j);
+                self.vec_znx_big_normalize(
+                    res_base2k,
+                    res_a.data_mut(),
+                    j,
+                    s_base2k,
+                    &res_big_tmp,
+                    0,
+                    scratch_2,
+                );
+            }
+
+            // res_b = a - (a - b) * bit = (b - a) * bit + a
+            for j in 0..(res_b.rank() + 1).into() {
+                self.vec_znx_big_sub_small_a(&mut res_big_tmp, 0, res_b.data(), j, &res_big, j);
+                self.vec_znx_big_normalize(
+                    res_base2k,
+                    res_b.data_mut(),
+                    j,
+                    s_base2k,
+                    &res_big_tmp,
+                    0,
+                    scratch_2,
+                );
+            }
+        } else {
+            let (mut tmp_a, scratch_1) = scratch.take_glwe(&GLWELayout {
+                n: res_a.n(),
+                base2k: s.base2k(),
+                k: res_a.k(),
+                rank: res_a.rank(),
+            });
+
+            let (mut tmp_b, scratch_2) = scratch_1.take_glwe(&GLWELayout {
+                n: res_b.n(),
+                base2k: s.base2k(),
+                k: res_b.k(),
+                rank: res_b.rank(),
+            });
+
+            self.glwe_normalize(&mut tmp_a, res_a, scratch_2);
+            self.glwe_normalize(&mut tmp_b, res_b, scratch_2);
+
+            let res_big: VecZnxBig<&mut [u8], BE>;
+            let (res_dft, scratch_3) = scratch_2.take_vec_znx_dft(self, (s.rank() + 1).into(), s.size()); // Todo optimise
+            {
+                // Temporary value storing a - b
+                let tmp_c_infos: GLWELayout = GLWELayout {
+                    n: s.n(),
+                    base2k: s.base2k(),
+                    k: res_a.k().max(res_b.k()),
+                    rank: s.rank(),
+                };
+                let (mut tmp_c, scratch_4) = scratch_3.take_glwe(&tmp_c_infos);
+                self.glwe_sub(&mut tmp_c, res_b, res_a);
+                res_big = self.glwe_external_product_internal(res_dft, &tmp_c, s, scratch_4);
+            }
+
+            // Single column res_big to store temporary value before normalization
+            let (mut res_big_tmp, scratch_4) = scratch_3.take_vec_znx_big::<_, BE>(self, 1, res_big.size());
+
+            // res_a = (b-a) * bit + a
+            for j in 0..(res_a.rank() + 1).into() {
+                self.vec_znx_big_add_small(&mut res_big_tmp, 0, &res_big, j, tmp_a.data(), j);
+                self.vec_znx_big_normalize(
+                    res_base2k,
+                    res_a.data_mut(),
+                    j,
+                    s_base2k,
+                    &res_big_tmp,
+                    0,
+                    scratch_4,
+                );
+            }
+
+            // res_b = a - (a - b) * bit = (b - a) * bit + a
+            for j in 0..(res_b.rank() + 1).into() {
+                self.vec_znx_big_sub_small_a(&mut res_big_tmp, 0, tmp_b.data(), j, &res_big, j);
+                self.vec_znx_big_normalize(
+                    res_base2k,
+                    res_b.data_mut(),
+                    j,
+                    s_base2k,
+                    &res_big_tmp,
+                    0,
+                    scratch_4,
+                );
+            }
+        }
+    }
+}
+
 pub trait Cmux<BE: Backend>
 where
     Self: Sized
@@ -284,6 +484,7 @@ .glwe_external_product_internal_tmp_bytes(res_infos, a_infos, b_infos)
                 .max(self.vec_znx_big_normalize_tmp_bytes())
     }
 
+    // res = (t - f) * s + f
     fn cmux<R, T, F, S>(&self, res: &mut R, t: &T, f: &F, s: &S, scratch: &mut Scratch<BE>)
     where
         R: GLWEToMut,
@@ -316,6 +517,46 @@ );
         }
     }
 
+    // res = (a - res) * s + res
+    fn cmux_inplace_neg<R, A, S>(&self, res: &mut R, a: &A, s: &S, scratch: &mut Scratch<BE>)
+    where
+        R: GLWEToMut,
+        A: GLWEToRef,
+        S: GGSWPreparedToRef<BE> + GGSWInfos,
+        Scratch<BE>: ScratchTakeCore<BE>,
+    {
+        let res: &mut GLWE<&mut [u8]> = &mut res.to_mut();
+        let s: &GGSWPrepared<&[u8], BE> = &s.to_ref();
+        let a: &GLWE<&[u8]> = &a.to_ref();
+
+        assert_eq!(res.base2k(), a.base2k());
+
+        let res_base2k: usize = res.base2k().into();
+        let ggsw_base2k: usize = s.base2k().into();
+        let (mut tmp, scratch_1) = scratch.take_glwe(&GLWELayout {
+            n: s.n(),
+            base2k: res.base2k(),
+            k: res.k().max(a.k()),
+            rank: res.rank(),
+        });
+        self.glwe_sub(&mut tmp, a, res);
+        let (res_dft, scratch_2) = scratch_1.take_vec_znx_dft(self, (res.rank() + 1).into(), s.size()); // Todo optimise
+        let mut res_big: VecZnxBig<&mut [u8], BE> = self.glwe_external_product_internal(res_dft, &tmp, s, scratch_2);
+        for j in 0..(res.rank() + 1).into() {
+            self.vec_znx_big_add_small_inplace(&mut res_big, j, res.data(), j);
+            self.vec_znx_big_normalize(
+                res_base2k,
+                res.data_mut(),
+                j,
+                ggsw_base2k,
+                &res_big,
+                j,
+                scratch_2,
+            );
+        }
+    }
+
+    // res = (res - a) * s + a
     fn cmux_inplace<R, A, S>(&self, res: &mut R, a: &A, s: &S, scratch: &mut Scratch<BE>)
     where
         R: GLWEToMut,

@@ -1,4 +1,5 @@
 mod bdd_2w_to_1w;
+mod blind_retrieval;
 mod blind_rotation;
 mod blind_selection;
 mod ciphertexts;
@@ -7,6 +8,7 @@ mod eval;
 mod key;
 
 pub use bdd_2w_to_1w::*;
+pub use blind_retrieval::*;
 pub use blind_rotation::*;
 pub use blind_selection::*;
 pub use ciphertexts::*;

@@ -6,7 +6,8 @@ use crate::tfhe::{
     bdd_arithmetic::tests::test_suite::{
         TestContext, test_bdd_add, test_bdd_and, test_bdd_or, test_bdd_prepare, test_bdd_sll, test_bdd_slt, test_bdd_sltu,
         test_bdd_sra, test_bdd_srl, test_bdd_sub, test_bdd_xor, test_fhe_uint_get_bit_glwe, test_fhe_uint_sext,
-        test_fhe_uint_splice_u8, test_fhe_uint_splice_u16, test_glwe_blind_selection, test_glwe_to_glwe_blind_rotation,
+        test_fhe_uint_splice_u8, test_fhe_uint_splice_u16, test_fhe_uint_swap, test_glwe_blind_retrieval_statefull,
+        test_glwe_blind_retriever, test_glwe_blind_selection, test_glwe_to_glwe_blind_rotation,
         test_scalar_to_ggsw_blind_rotation,
     },
     blind_rotation::CGGI,
@@ -14,6 +15,21 @@ };
 
 static TEST_CONTEXT_CGGI_FFT64_REF: LazyLock<TestContext<CGGI, FFT64Ref>> =
     LazyLock::new(|| TestContext::<CGGI, FFT64Ref>::new());
+
+#[test]
+fn test_glwe_blind_retriever_fft64_ref() {
+    test_glwe_blind_retriever(&TEST_CONTEXT_CGGI_FFT64_REF);
+}
+
+#[test]
+fn test_glwe_blind_retrieval_statefull_fft64_ref() {
+    test_glwe_blind_retrieval_statefull(&TEST_CONTEXT_CGGI_FFT64_REF);
+}
+
+#[test]
+fn test_fhe_uint_swap_fft64_ref() {
+    test_fhe_uint_swap(&TEST_CONTEXT_CGGI_FFT64_REF);
+}
 
 #[test]
 fn test_fhe_uint_get_bit_glwe_fft64_ref() {

@@ -12,6 +12,7 @@ mod sltu;
 mod sra;
 mod srl;
 mod sub;
+mod swap;
 mod xor;
 
 pub use add::*;
@@ -33,6 +34,7 @@ pub use sltu::*;
 pub use sra::*;
 pub use srl::*;
 pub use sub::*;
+pub use swap::*;
 pub use xor::*;
 
 use poulpy_core::{

@@ -0,0 +1,203 @@
+use itertools::Itertools;
+use poulpy_core::{
+    GGSWEncryptSk, GLWEDecrypt, GLWEEncryptSk,
+    layouts::{GGSW, GGSWPrepared, GGSWPreparedFactory, GLWELayout, GLWESecretPrepared},
+};
+use poulpy_hal::{
+    api::{ScratchOwnedAlloc, ScratchOwnedBorrow},
+    layouts::{Backend, Module, ScalarZnx, Scratch, ScratchOwned, ZnxViewMut},
+    source::Source,
+};
+use rand::RngCore;
+
+use crate::tfhe::{
+    bdd_arithmetic::{
+        Cswap, FheUint, FheUintPrepared, GLWEBlindRetrieval, GLWEBlindRetriever, ScratchTakeBDD,
+        tests::test_suite::{TEST_GGSW_INFOS, TEST_GLWE_INFOS, TestContext},
+    },
+    blind_rotation::BlindRotationAlgo,
+};
+
+pub fn test_fhe_uint_swap<BRA: BlindRotationAlgo, BE: Backend>(test_context: &TestContext<BRA, BE>)
+where
+    Module<BE>: GLWEEncryptSk<BE> + GLWEDecrypt<BE> + Cswap<BE> + GGSWEncryptSk<BE> + GGSWPreparedFactory<BE>,
+    ScratchOwned<BE>: ScratchOwnedAlloc<BE> + ScratchOwnedBorrow<BE>,
+    Scratch<BE>: ScratchTakeBDD<u32, BE>,
+{
+    let glwe_infos: GLWELayout = TEST_GLWE_INFOS;
+    let ggsw_infos: poulpy_core::layouts::GGSWLayout = TEST_GGSW_INFOS;
+
+    let module: &Module<BE> = &test_context.module;
+    let sk: &GLWESecretPrepared<Vec<u8>, BE> = &test_context.sk_glwe;
+
+    let mut source_xa: Source = Source::new([2u8; 32]);
+    let mut source_xe: Source = Source::new([3u8; 32]);
+
+    let mut scratch: ScratchOwned<BE> = ScratchOwned::alloc(1 << 22);
+
+    let mut s: GGSW<Vec<u8>> = GGSW::alloc_from_infos(&ggsw_infos);
+    let mut s_prepared: GGSWPrepared<Vec<u8>, BE> = GGSWPrepared::alloc_from_infos(module, &ggsw_infos);
+
+    let a: u32 = source_xa.next_u32();
+    let b: u32 = source_xa.next_u32();
+
+    for bit in [0, 1] {
+        let mut a_enc: FheUint<Vec<u8>, u32> = FheUint::<Vec<u8>, u32>::alloc_from_infos(&glwe_infos);
+        let mut b_enc: FheUint<Vec<u8>, u32> = FheUint::<Vec<u8>, u32>::alloc_from_infos(&glwe_infos);
+
+        a_enc.encrypt_sk(
+            module,
+            a,
+            sk,
+            &mut source_xa,
+            &mut source_xe,
+            scratch.borrow(),
+        );
+
+        b_enc.encrypt_sk(
+            module,
+            b,
+            sk,
+            &mut source_xa,
+            &mut source_xe,
+            scratch.borrow(),
+        );
+
+        let mut pt: ScalarZnx<Vec<u8>> = ScalarZnx::alloc(module.n(), 1);
+        pt.raw_mut()[0] = bit;
+        s.encrypt_sk(
+            module,
+            &pt,
+            sk,
+            &mut source_xa,
+            &mut source_xe,
+            scratch.borrow(),
+        );
+        s_prepared.prepare(module, &s, scratch.borrow());
+
+        module.cswap(&mut a_enc, &mut b_enc, &s_prepared, scratch.borrow());
+
+        let (a_want, b_want) = if bit == 0 { (a, b) } else { (b, a) };
+
+        assert_eq!(a_want, a_enc.decrypt(module, sk, scratch.borrow()));
+        assert_eq!(b_want, b_enc.decrypt(module, sk, scratch.borrow()));
+    }
+}
+
+pub fn test_glwe_blind_retrieval_statefull<BRA: BlindRotationAlgo, BE: Backend>(test_context: &TestContext<BRA, BE>)
+where
+    Module<BE>: GLWEEncryptSk<BE> + GLWEDecrypt<BE> + GLWEBlindRetrieval<BE> + GGSWEncryptSk<BE> + GGSWPreparedFactory<BE>,
+    ScratchOwned<BE>: ScratchOwnedAlloc<BE> + ScratchOwnedBorrow<BE>,
+    Scratch<BE>: ScratchTakeBDD<u32, BE>,
+{
+    let glwe_infos: GLWELayout = TEST_GLWE_INFOS;
+    let ggsw_infos: poulpy_core::layouts::GGSWLayout = TEST_GGSW_INFOS;
+
+    let module: &Module<BE> = &test_context.module;
+    let sk: &GLWESecretPrepared<Vec<u8>, BE> = &test_context.sk_glwe;
+
+    let mut source_xa: Source = Source::new([2u8; 32]);
+    let mut source_xe: Source = Source::new([3u8; 32]);
+
+    let mut scratch: ScratchOwned<BE> = ScratchOwned::alloc(1 << 22);
+
+    let data: Vec<u32> = (0..25).map(|i| i as u32).collect_vec();
+
+    let mut data_enc: Vec<FheUint<Vec<u8>, u32>> = (0..data.len())
+        .map(|i| {
+            let mut ct: FheUint<Vec<u8>, u32> = FheUint::<Vec<u8>, u32>::alloc_from_infos(&glwe_infos);
+            ct.encrypt_sk(
+                module,
+                data[i],
+                sk,
+                &mut source_xa,
+                &mut source_xe,
+                scratch.borrow(),
+            );
+            ct
+        })
+        .collect_vec();
+
+    for idx in 0..data.len() as u32 {
+        let mut idx_enc = FheUintPrepared::alloc_from_infos(module, &ggsw_infos);
+        idx_enc.encrypt_sk(
+            module,
+            idx,
+            sk,
+            &mut source_xa,
+            &mut source_xe,
+            scratch.borrow(),
+        );
+
+        module.glwe_blind_retrieval_statefull(&mut data_enc, &idx_enc, 0, 5, scratch.borrow());
+
+        assert_eq!(
+            data[idx as usize],
+            data_enc[0].decrypt(module, sk, scratch.borrow())
+        );
+
+        module.glwe_blind_retrieval_statefull_rev(&mut data_enc, &idx_enc, 0, 5, scratch.borrow());
+
+        for i in 0..data.len() {
+            assert_eq!(data[i], data_enc[i].decrypt(module, sk, scratch.borrow()))
+        }
+    }
+}
+
+pub fn test_glwe_blind_retriever<BRA: BlindRotationAlgo, BE: Backend>(test_context: &TestContext<BRA, BE>)
+where
+    Module<BE>: GLWEEncryptSk<BE> + GLWEDecrypt<BE> + GLWEBlindRetrieval<BE> + GGSWEncryptSk<BE> + GGSWPreparedFactory<BE>,
+    ScratchOwned<BE>: ScratchOwnedAlloc<BE> + ScratchOwnedBorrow<BE>,
+    Scratch<BE>: ScratchTakeBDD<u32, BE>,
+{
+    let glwe_infos: GLWELayout = TEST_GLWE_INFOS;
+    let ggsw_infos: poulpy_core::layouts::GGSWLayout = TEST_GGSW_INFOS;
+
+    let module: &Module<BE> = &test_context.module;
+    let sk: &GLWESecretPrepared<Vec<u8>, BE> = &test_context.sk_glwe;
+
+    let mut source_xa: Source = Source::new([2u8; 32]);
+    let mut source_xe: Source = Source::new([3u8; 32]);
+
+    let mut scratch: ScratchOwned<BE> = ScratchOwned::alloc(1 << 22);
+
+    let data: Vec<u32> = (0..25).map(|i| i as u32).collect_vec();
+
+    let data_enc: Vec<FheUint<Vec<u8>, u32>> = (0..data.len())
+        .map(|i| {
+            let mut ct: FheUint<Vec<u8>, u32> = FheUint::<Vec<u8>, u32>::alloc_from_infos(&glwe_infos);
+            ct.encrypt_sk(
+                module,
+                data[i],
+                sk,
+                &mut source_xa,
+                &mut source_xe,
+                scratch.borrow(),
+            );
+            ct
+        })
+        .collect_vec();
+
+    for idx in 0..data.len() as u32 {
+        let mut idx_enc: FheUintPrepared<Vec<u8>, u32, BE> = FheUintPrepared::alloc_from_infos(module, &ggsw_infos);
+        idx_enc.encrypt_sk(
+            module,
+            idx,
+            sk,
+            &mut source_xa,
+            &mut source_xe,
+            scratch.borrow(),
+        );
+
+        let mut retriever: GLWEBlindRetriever = GLWEBlindRetriever::alloc(&glwe_infos, 25);
+        let mut res: FheUint<Vec<u8>, u32> = FheUint::alloc_from_infos(&glwe_infos);
+        retriever.retrieve(module, &mut res, &data_enc, &idx_enc, scratch.borrow());
+
+        println!("{}", res.decrypt(module, sk, scratch.borrow()));
+
+        assert_eq!(
+            data[idx as usize],
+            res.decrypt(module, sk, scratch.borrow())
+        );
+    }
+}