diff --git a/rlwe/src/elem.rs b/rlwe/src/elem.rs
index 7574bf5..5749208 100644
--- a/rlwe/src/elem.rs
+++ b/rlwe/src/elem.rs
@@ -1,4 +1,4 @@
-use base2k::{Backend, FFT64, MatZnxDft, MatZnxDftAlloc, Module, VecZnx, VecZnxAlloc};
+use base2k::{Backend, FFT64, MatZnxDft, MatZnxDftAlloc, Module, VecZnx, VecZnxAlloc, VecZnxDft, VecZnxDftAlloc};
 
 pub struct Ciphertext<T> {
     data: T,
@@ -48,7 +48,12 @@ impl<T> Plaintext<T> {
     }
 }
 
-pub(crate) type CipherVecZnx<C> = Ciphertext<VecZnx<C>>;
+pub(crate) type CtVecZnx<C> = Ciphertext<VecZnx<C>>;
+pub(crate) type CtVecZnxDft<C, B: Backend> = Ciphertext<VecZnxDft<C, B>>;
+pub(crate) type CtMatZnxDft<C, B: Backend> = Ciphertext<MatZnxDft<C, B>>;
+pub(crate) type PtVecZnx<C> = Plaintext<VecZnx<C>>;
+pub(crate) type PtVecZnxDft<C, B: Backend> = Plaintext<VecZnxDft<C, B>>;
+pub(crate) type PtMatZnxDft<C, B: Backend> = Plaintext<MatZnxDft<C, B>>;
 
 impl Ciphertext<VecZnx<Vec<u8>>> {
     pub fn new<B: Backend>(module: &Module<B>, log_base2k: usize, log_q: usize, cols: usize) -> Self {
@@ -70,6 +75,16 @@ impl Plaintext<VecZnx<Vec<u8>>> {
     }
 }
 
+impl<B: Backend> Ciphertext<VecZnxDft<Vec<u8>, B>> {
+    pub fn new(module: &Module<B>, log_base2k: usize, log_q: usize, cols: usize) -> Self {
+        Self {
+            data: module.new_vec_znx_dft(cols, derive_size(log_base2k, log_q)),
+            log_base2k: log_base2k,
+            log_q: log_q,
+        }
+    }
+}
+
 impl<B: Backend> Ciphertext<MatZnxDft<Vec<u8>, B>> {
     pub fn new(module: &Module<B>, log_base2k: usize, rows: usize, cols_in: usize, cols_out: usize, log_q: usize) -> Self {
         Self {
diff --git a/rlwe/src/encryption.rs b/rlwe/src/encryption.rs
index 3b291f9..3d62bfe 100644
--- a/rlwe/src/encryption.rs
+++ b/rlwe/src/encryption.rs
@@ -1,20 +1,21 @@
 use base2k::{
-    AddNormal, Backend, FFT64, FillUniform, Module, ScalarZnxDftOps, ScalarZnxDftToRef, Scratch, VecZnx, VecZnxBigAlloc,
-    VecZnxBigOps, VecZnxBigScratch, VecZnxDftAlloc, VecZnxDftOps, VecZnxToMut, VecZnxToRef, ZnxInfos,
+    AddNormal, Backend, FFT64, FillUniform, Module, ScalarZnxDftOps, ScalarZnxDftToRef, Scratch, VecZnx, VecZnxAlloc,
+    VecZnxBigAlloc, VecZnxBigOps, VecZnxBigScratch, VecZnxDft, VecZnxDftAlloc, VecZnxDftOps, VecZnxDftToMut, VecZnxDftToRef,
+    VecZnxToMut, VecZnxToRef, ZnxInfos,
 };
 
 use sampling::source::Source;
 
 use crate::{
-    elem::{CipherVecZnx, Plaintext},
+    elem::{CtVecZnx, CtVecZnxDft, PtVecZnx},
     keys::SecretKey,
 };
 
-pub trait EncryptSk<B: Backend, D> {
-    fn encrypt<P, S>(
+pub trait EncryptSk<B: Backend, D, P> {
+    fn encrypt<S>(
         module: &Module<B>,
         res: &mut D,
-        pt: Option<&Plaintext<P>>,
+        pt: Option<&P>,
         sk: &SecretKey<S>,
         source_xa: &mut Source,
         source_xe: &mut Source,
@@ -22,7 +23,6 @@ pub trait EncryptSk<B: Backend, D> {
         sigma: f64,
         bound: f64,
     ) where
-        P: VecZnxToRef,
         S: ScalarZnxDftToRef<B>;
 
     fn encrypt_tmp_bytes(module: &Module<B>, size: usize) -> usize {
@@ -30,14 +30,15 @@ pub trait EncryptSk<B: Backend, D> {
     }
 }
 
-impl<C> EncryptSk<FFT64, CipherVecZnx<C>> for CipherVecZnx<C>
+impl<C, P> EncryptSk<FFT64, CtVecZnx<C>, PtVecZnx<P>> for CtVecZnx<C>
 where
     VecZnx<C>: VecZnxToMut + VecZnxToRef,
+    VecZnx<P>: VecZnxToRef,
 {
-    fn encrypt<P, S>(
+    fn encrypt<S>(
         module: &Module<FFT64>,
-        ct: &mut CipherVecZnx<C>,
-        pt: Option<&Plaintext<P>>,
+        ct: &mut CtVecZnx<C>,
+        pt: Option<&PtVecZnx<P>>,
         sk: &SecretKey<S>,
         source_xa: &mut Source,
         source_xe: &mut Source,
@@ -45,7 +46,6 @@ where
         sigma: f64,
         bound: f64,
     ) where
-        P: VecZnxToRef,
         S: ScalarZnxDftToRef<FFT64>,
     {
         let log_base2k: usize = ct.log_base2k();
@@ -60,9 +60,10 @@ where
 
         {
             let (mut c0_dft, _) = scratch_1.tmp_vec_znx_dft(module, 1, size);
+            module.vec_znx_dft(&mut c0_dft, 0, &ct_mut, 1);
 
             // c0_dft = DFT(a) * DFT(s)
-            module.svp_apply(&mut c0_dft, 0, &sk.data().to_ref(), 0, &ct_mut, 1);
+            module.svp_apply_inplace(&mut c0_dft, 0, &sk.data().to_ref(), 0);
 
             // c0_big = IDFT(c0_dft)
             module.vec_znx_idft_tmp_a(&mut c0_big, 0, &mut c0_dft, 0);
@@ -79,3 +80,73 @@ where
         module.vec_znx_big_normalize(log_base2k, &mut ct_mut, 0, &c0_big, 0, scratch_1);
     }
 }
+
+pub trait EncryptZeroSk<B: Backend, D> {
+    fn encrypt_zero<S>(
+        module: &Module<B>,
+        res: &mut D,
+        sk: &SecretKey<S>,
+        source_xa: &mut Source,
+        source_xe: &mut Source,
+        scratch: &mut Scratch,
+        sigma: f64,
+        bound: f64,
+    ) where
+        S: ScalarZnxDftToRef<B>;
+
+    fn encrypt_zero_tmp_bytes(module: &Module<B>, size: usize) -> usize {
+        (module.bytes_of_vec_znx(1, size) | module.bytes_of_vec_znx_dft(1, size))
+            + module.bytes_of_vec_znx_big(1, size)
+            + module.bytes_of_vec_znx(1, size)
+            + module.vec_znx_big_normalize_tmp_bytes()
+    }
+}
+
+impl<C> EncryptZeroSk<FFT64, CtVecZnxDft<C, FFT64>> for CtVecZnxDft<C, FFT64>
+where
+    VecZnxDft<C, FFT64>: VecZnxDftToMut<FFT64> + VecZnxDftToRef<FFT64>,
+{
+    fn encrypt_zero<S>(
+        module: &Module<FFT64>,
+        ct: &mut CtVecZnxDft<C, FFT64>,
+        sk: &SecretKey<S>,
+        source_xa: &mut Source,
+        source_xe: &mut Source,
+        scratch: &mut Scratch,
+        sigma: f64,
+        bound: f64,
+    ) where
+        S: ScalarZnxDftToRef<FFT64>,
+    {
+        let log_base2k: usize = ct.log_base2k();
+        let log_q: usize = ct.log_q();
+        let mut ct_mut: VecZnxDft<&mut [u8], FFT64> = ct.data_mut().to_mut();
+        let size: usize = ct_mut.size();
+
+        // ct[1] = DFT(a)
+        {
+            let (mut tmp_znx, _) = scratch.tmp_vec_znx(module, 1, size);
+            tmp_znx.fill_uniform(log_base2k, 1, size, source_xa);
+            module.vec_znx_dft(&mut ct_mut, 1, &tmp_znx, 0);
+        }
+
+        let (mut c0_big, scratch_1) = scratch.tmp_vec_znx_big(module, 1, size);
+
+        {
+            let (mut tmp_dft, _) = scratch_1.tmp_vec_znx_dft(module, 1, size);
+            // c0_dft = DFT(a) * DFT(s)
+            module.svp_apply(&mut tmp_dft, 0, &sk.data().to_ref(), 0, &ct_mut, 1);
+            // c0_big = IDFT(c0_dft)
+            module.vec_znx_idft_tmp_a(&mut c0_big, 0, &mut tmp_dft, 0);
+        }
+
+        // c0_big += e
+        c0_big.add_normal(log_base2k, 0, log_q, source_xe, sigma, bound);
+
+        // c0 = norm(c0_big = -as + e)
+        let (mut tmp_znx, scratch_2) = scratch_1.tmp_vec_znx(module, 1, size);
+        module.vec_znx_big_normalize(log_base2k, &mut tmp_znx, 0, &c0_big, 0, scratch_2);
+        // ct[0] = DFT(-as + e)
+        module.vec_znx_dft(&mut ct_mut, 0, &tmp_znx, 0);
+    }
+}
diff --git a/rlwe/src/keys.rs b/rlwe/src/keys.rs
index 50f1221..d84abc0 100644
--- a/rlwe/src/keys.rs
+++ b/rlwe/src/keys.rs
@@ -15,7 +15,7 @@ impl<T> SecretKey<T> {
         &self.data
     }
 
-    pub fn data_mut(&self) -> &mut T {
+    pub fn data_mut(&mut self) -> &mut T {
         &mut self.data
     }
 }