diff --git a/core/src/ggsw/ciphertext.rs b/core/src/ggsw/ciphertext.rs
index e52f305..13049f5 100644
--- a/core/src/ggsw/ciphertext.rs
+++ b/core/src/ggsw/ciphertext.rs
@@ -20,6 +20,8 @@ pub struct GGSWCiphertext<C, B: Backend> {
 impl GGSWCiphertext<Vec<u8>, FFT64> {
     pub fn alloc(module: &Module<FFT64>, basek: usize, k: usize, rows: usize, digits: usize, rank: usize) -> Self {
         let size: usize = k.div_ceil(basek);
+        debug_assert!(digits > 0, "invalid ggsw: `digits` == 0");
+
         debug_assert!(
             size > digits,
             "invalid ggsw: ceil(k/basek): {} <= digits: {}",
diff --git a/core/src/glwe/ciphertext.rs b/core/src/glwe/ciphertext.rs
index d0fb39c..07b4264 100644
--- a/core/src/glwe/ciphertext.rs
+++ b/core/src/glwe/ciphertext.rs
@@ -79,7 +79,7 @@ impl<DataSelf: AsMut<[u8]> + AsRef<[u8]>> SetMetaData for GLWECiphertext<DataSel
     }
 }
 
-pub trait GLWECiphertextToRef {
+pub trait GLWECiphertextToRef: Infos {
     fn to_ref(&self) -> GLWECiphertext<&[u8]>;
 }
 
@@ -93,7 +93,7 @@ impl<D: AsRef<[u8]>> GLWECiphertextToRef for GLWECiphertext<D> {
     }
 }
 
-pub trait GLWECiphertextToMut {
+pub trait GLWECiphertextToMut: Infos {
     fn to_mut(&mut self) -> GLWECiphertext<&mut [u8]>;
 }
 
diff --git a/core/src/glwe/ops.rs b/core/src/glwe/ops.rs
index d921583..9248e85 100644
--- a/core/src/glwe/ops.rs
+++ b/core/src/glwe/ops.rs
@@ -2,11 +2,11 @@ use backend::{FFT64, Module, Scratch, VecZnx, VecZnxOps, ZnxZero};
 
 use crate::{GLWECiphertext, GLWECiphertextToMut, GLWECiphertextToRef, Infos, SetMetaData};
 
-pub trait GLWEOps: GLWECiphertextToMut + Infos + SetMetaData {
+pub trait GLWEOps: GLWECiphertextToMut + SetMetaData {
     fn add<A, B>(&mut self, module: &Module<FFT64>, a: &A, b: &B)
     where
-        A: GLWECiphertextToRef + Infos,
-        B: GLWECiphertextToRef + Infos,
+        A: GLWECiphertextToRef,
+        B: GLWECiphertextToRef,
     {
         #[cfg(debug_assertions)]
         {
@@ -75,8 +75,8 @@ pub trait GLWEOps: GLWECiphertextToMut + Infos + SetMetaData {
 
     fn sub<A, B>(&mut self, module: &Module<FFT64>, a: &A, b: &B)
     where
-        A: GLWECiphertextToRef + Infos,
-        B: GLWECiphertextToRef + Infos,
+        A: GLWECiphertextToRef,
+        B: GLWECiphertextToRef,
     {
         #[cfg(debug_assertions)]
         {
@@ -230,7 +230,7 @@ pub trait GLWEOps: GLWECiphertextToMut + Infos + SetMetaData {
 
     fn normalize<A>(&mut self, module: &Module<FFT64>, a: &A, scratch: &mut Scratch)
     where
-        A: GLWECiphertextToRef + Infos,
+        A: GLWECiphertextToRef,
     {
         #[cfg(debug_assertions)]
         {