diff --git a/lee/state_machine/src/signature/private_key.rs b/lee/state_machine/src/signature/private_key.rs
index 4f05ba80..c13be154 100644
--- a/lee/state_machine/src/signature/private_key.rs
+++ b/lee/state_machine/src/signature/private_key.rs
@@ -74,7 +74,8 @@ impl PrivateKey {
 
         let sk = k256::SecretKey::from_slice(value).map_err(|_e| LeeError::InvalidPrivateKey)?;
 
-        let hashed: [u8; 32] = Sha256::digest(sk.public_key().to_encoded_point(true).as_bytes()).into();
+        let hashed: [u8; 32] =
+            Sha256::digest(sk.public_key().to_encoded_point(true).as_bytes()).into();
 
         let sk = sk.to_nonzero_scalar();
 
diff --git a/lez/keycard_wallet/keycard_applets/LEE_keycard.cap b/lez/keycard_wallet/keycard_applets/LEE_keycard.cap
index b44835c4..b2e71d56 100644
Binary files a/lez/keycard_wallet/keycard_applets/LEE_keycard.cap and b/lez/keycard_wallet/keycard_applets/LEE_keycard.cap differ
diff --git a/lez/keycard_wallet/src/lib.rs b/lez/keycard_wallet/src/lib.rs
index 1f009900..93f55756 100644
--- a/lez/keycard_wallet/src/lib.rs
+++ b/lez/keycard_wallet/src/lib.rs
@@ -7,8 +7,9 @@ use zeroize::Zeroizing;
 
 pub mod python_path;
 
-/// NSK and VSK as fixed-length zeroizing byte arrays.
-type PrivateKeyPair = (Zeroizing<[u8; 32]>, Zeroizing<[u8; 32]>);
+/// NSK (32 bytes) and VSK (64 bytes, the ML-KEM-768 seed `d || z`) as fixed-length zeroizing byte
+/// arrays.
+type PrivateKeyPair = (Zeroizing<[u8; 32]>, Zeroizing<[u8; 64]>);
 
 // TODO: encrypt at rest alongside broader wallet storage encryption work.
 #[derive(Serialize, Deserialize)]
@@ -239,13 +240,13 @@ impl KeycardWallet {
         };
 
         let vsk = {
-            if raw_vsk.len() != 32 {
+            if raw_vsk.len() != 64 {
                 return Err(PyErr::new::<pyo3::exceptions::PyValueError, _>(format!(
-                    "expected 32-byte VSK from keycard, got {} bytes",
+                    "expected 64-byte VSK from keycard, got {} bytes",
                     raw_vsk.len()
                 )));
             }
-            let mut arr = Zeroizing::new([0_u8; 32]);
+            let mut arr = Zeroizing::new([0_u8; 64]);
             arr.copy_from_slice(&raw_vsk);
             arr
         };