diff --git a/common/src/block.rs b/common/src/block.rs
index 52069134..3f354c2d 100644
--- a/common/src/block.rs
+++ b/common/src/block.rs
@@ -85,8 +85,19 @@ impl HashableBlockData {
         signing_key: &nssa::PrivateKey,
         bedrock_parent_id: MantleMsgId,
     ) -> Block {
+        const PREFIX: &[u8; 32] = b"/LEE/v0.3/Message/Block/\x00\x00\x00\x00\x00\x00\x00\x00";
+
         let data_bytes = borsh::to_vec(&self).unwrap();
-        let hash = OwnHasher::hash(&data_bytes);
+        let mut bytes = Vec::with_capacity(
+            PREFIX
+                .len()
+                .checked_add(data_bytes.len())
+                .expect("length overflow"),
+        );
+        bytes.extend_from_slice(PREFIX);
+        bytes.extend_from_slice(&data_bytes);
+
+        let hash = OwnHasher::hash(&bytes);
         let signature = nssa::Signature::new(signing_key, &hash.0);
         Block {
             header: BlockHeader {
diff --git a/nssa/src/privacy_preserving_transaction/message.rs b/nssa/src/privacy_preserving_transaction/message.rs
index 1030b399..5e03a26d 100644
--- a/nssa/src/privacy_preserving_transaction/message.rs
+++ b/nssa/src/privacy_preserving_transaction/message.rs
@@ -121,7 +121,18 @@ impl Message {
 
     #[must_use]
     pub fn hash_message(&self) -> [u8; 32] {
-        Sha256::digest(self.to_bytes()).into()
+        const PREFIX: &[u8; 32] = b"/LEE/v0.3/Message/Privacy/\x00\x00\x00\x00\x00\x00";
+
+        let mut bytes = Vec::with_capacity(
+            PREFIX
+                .len()
+                .checked_add(self.to_bytes().len())
+                .expect("length overflow"),
+        );
+        bytes.extend_from_slice(PREFIX);
+        bytes.extend_from_slice(&self.to_bytes());
+
+        Sha256::digest(bytes).into()
     }
 }
 
diff --git a/nssa/src/privacy_preserving_transaction/witness_set.rs b/nssa/src/privacy_preserving_transaction/witness_set.rs
index 9578e728..d7685a77 100644
--- a/nssa/src/privacy_preserving_transaction/witness_set.rs
+++ b/nssa/src/privacy_preserving_transaction/witness_set.rs
@@ -13,6 +13,8 @@ pub struct WitnessSet {
 
 impl WitnessSet {
     #[must_use]
+    // TODO: swap for Keycard signing path.
+    // However. we may need to get signatures from Keycard.
     pub fn for_message(message: &Message, proof: Proof, private_keys: &[&PrivateKey]) -> Self {
         let message_hash = message.hash_message();
         let signatures_and_public_keys = private_keys
diff --git a/nssa/src/public_transaction/message.rs b/nssa/src/public_transaction/message.rs
index 2663c16c..03e790af 100644
--- a/nssa/src/public_transaction/message.rs
+++ b/nssa/src/public_transaction/message.rs
@@ -67,6 +67,17 @@ impl Message {
 
     #[must_use]
     pub fn hash_message(&self) -> [u8; 32] {
-        Sha256::digest(self.to_bytes()).into()
+        const PREFIX: &[u8; 32] = b"/LEE/v0.3/Message/Public/\x00\x00\x00\x00\x00\x00\x00";
+
+        let mut bytes = Vec::with_capacity(
+            PREFIX
+                .len()
+                .checked_add(self.to_bytes().len())
+                .expect("length overflow"),
+        );
+        bytes.extend_from_slice(PREFIX);
+        bytes.extend_from_slice(&self.to_bytes());
+
+        Sha256::digest(bytes).into()
     }
 }
diff --git a/nssa/src/signature/bip340_test_vectors.rs b/nssa/src/signature/bip340_test_vectors.rs
index c5a80bb4..ac3eb044 100644
--- a/nssa/src/signature/bip340_test_vectors.rs
+++ b/nssa/src/signature/bip340_test_vectors.rs
@@ -4,7 +4,7 @@ pub struct TestVector {
     pub seckey: Option<PrivateKey>,
     pub pubkey: PublicKey,
     pub aux_rand: Option<[u8; 32]>,
-    pub message: Option<[u8; 32]>,
+    pub message: [u8; 32],
     pub signature: Signature,
     pub verification_result: bool,
 }
@@ -28,9 +28,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             aux_rand: Some(hex_to_bytes::<32>(
                 "0000000000000000000000000000000000000000000000000000000000000000",
             )),
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "0000000000000000000000000000000000000000000000000000000000000000",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "E907831F80848D1069A5371B402410364BDF1C5F8307B0084C55F1CE2DCA821525F66A4A85EA8B71E482A74F382D2CE5EBEEE8FDB2172F477DF4900D310536C0",
@@ -52,9 +52,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             aux_rand: Some(hex_to_bytes::<32>(
                 "0000000000000000000000000000000000000000000000000000000000000001",
             )),
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "6896BD60EEAE296DB48A229FF71DFE071BDE413E6D43F917DC8DCF8C78DE33418906D11AC976ABCCB20B091292BFF4EA897EFCB639EA871CFA95F6DE339E4B0A",
@@ -76,9 +76,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             aux_rand: Some(hex_to_bytes::<32>(
                 "C87AA53824B4D7AE2EB035A2B5BBBCCC080E76CDC6D1692C4B0B62D798E6D906",
             )),
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "7E2D58D8B3BCDF1ABADEC7829054F90DDA9805AAB56C77333024B9D0A508B75C",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "5831AAEED7B44BB74E5EAB94BA9D4294C49BCF2A60728D8B4C200F50DD313C1BAB745879A5AD954A72C45A91C3A51D3C7ADEA98D82F8481E0E1E03674A6F3FB7",
@@ -100,9 +100,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             aux_rand: Some(hex_to_bytes::<32>(
                 "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",
             )),
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "7EB0509757E246F19449885651611CB965ECC1A187DD51B64FDA1EDC9637D5EC97582B9CB13DB3933705B32BA982AF5AF25FD78881EBB32771FC5922EFC66EA3",
@@ -117,9 +117,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "4DF3C3F68FCC83B27E9D42C90431A72499F17875C81A599B566C9889B9696703",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "00000000000000000000003B78CE563F89A0ED9414F5AA28AD0D96D6795F9C6376AFB1548AF603B3EB45C9F8207DEE1060CB71C04E80F593060B07D28308D7F4",
@@ -134,7 +134,7 @@ pub fn test_vectors() -> Vec<TestVector> {
         //                     "EEFDEA4CDB677750A420FEE807EACF21EB9898AE79B9768766E4FAA04A2D4A34",
         //                 )).unwrap(),
         //     aux_rand: None,
-        //     message: Some(
+        //     message:
         //
         // hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89").
         // unwrap(),                 ),
@@ -153,9 +153,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "FFF97BD5755EEEA420453A14355235D382F6472F8568A18B2F057A14602975563CC27944640AC607CD107AE10923D9EF7A73C643E166BE5EBEAFA34B1AC553E2",
@@ -170,9 +170,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "1FA62E331EDBC21C394792D2AB1100A7B432B013DF3F6FF4F99FCB33E0E1515F28890B3EDB6E7189B630448B515CE4F8622A954CFE545735AAEA5134FCCDB2BD",
@@ -187,9 +187,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "6CFF5C3BA86C69EA4B7376F31A9BCB4F74C1976089B2D9963DA2E5543E177769961764B3AA9B2FFCB6EF947B6887A226E8D7C93E00C5ED0C1834FF0D0C2E6DA6",
@@ -204,9 +204,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "0000000000000000000000000000000000000000000000000000000000000000123DDA8328AF9C23A94C1FEECFD123BA4FB73476F0D594DCB65C6425BD186051",
@@ -221,9 +221,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "00000000000000000000000000000000000000000000000000000000000000017615FBAF5AE28864013C099742DEADB4DBA87F11AC6754F93780D5A1837CF197",
@@ -238,9 +238,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "4A298DACAE57395A15D0795DDBFD1DCB564DA82B0F269BC70A74F8220429BA1D69E89B4C5564D00349106B8497785DD7D1D713A8AE82B32FA79D5F7FC407D39B",
@@ -255,9 +255,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F69E89B4C5564D00349106B8497785DD7D1D713A8AE82B32FA79D5F7FC407D39B",
@@ -272,9 +272,9 @@ pub fn test_vectors() -> Vec<TestVector> {
             ))
             .unwrap(),
             aux_rand: None,
-            message: Some(hex_to_bytes::<32>(
+            message: hex_to_bytes::<32>(
                 "243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89",
-            )),
+            ),
             signature: Signature {
                 value: hex_to_bytes(
                     "6CFF5C3BA86C69EA4B7376F31A9BCB4F74C1976089B2D9963DA2E5543E177769FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141",
@@ -289,7 +289,7 @@ pub fn test_vectors() -> Vec<TestVector> {
         //                     "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC30",
         //                 )).unwrap(),
         //     aux_rand: None,
-        //     message: Some(
+        //     message:
         //
         // hex::decode("243F6A8885A308D313198A2E03707344A4093822299F31D0082EFA98EC4E6C89").
         // unwrap(),                 ),
@@ -303,13 +303,13 @@ pub fn test_vectors() -> Vec<TestVector> {
         // },
         // Test with invalid message length (0); valid test for BIP-340 post 2022.
         // TestVector {
-        // seckey: Some(PrivateKey::try_new(hex_to_bytes(
+        // seckey: PrivateKey::try_new(hex_to_bytes(
         // "0340034003400340034003400340034003400340034003400340034003400340",
         // )).unwrap()),
         // pubkey: PublicKey::try_new(hex_to_bytes(
         // "778CAA53B4393AC467774D09497A87224BF9FAB6F6E68B23086497324D6FD117",
         // )).unwrap(),
-        // aux_rand: Some(hex_to_bytes::<32>(
+        // aux_rand: hex_to_bytes::<32>(
         // "0000000000000000000000000000000000000000000000000000000000000000",
         // )),
         // message: None,
@@ -322,16 +322,16 @@ pub fn test_vectors() -> Vec<TestVector> {
         // },
         // Test with invalid message length (1); valid test for BIP-340 post 2022.
         // TestVector {
-        // seckey: Some(PrivateKey::try_new(hex_to_bytes(
+        // seckey: PrivateKey::try_new(hex_to_bytes(
         // "0340034003400340034003400340034003400340034003400340034003400340",
         // )).unwrap()),
         // pubkey: PublicKey::try_new(hex_to_bytes(
         // "778CAA53B4393AC467774D09497A87224BF9FAB6F6E68B23086497324D6FD117",
         // )).unwrap(),
-        // aux_rand: Some(hex_to_bytes::<32>(
+        // aux_rand: hex_to_bytes::<32>(
         // "0000000000000000000000000000000000000000000000000000000000000000",
         // )),
-        // message: Some(hex::decode("11").unwrap()),
+        // message: hex::decode("11").unwrap()),
         // signature: Signature {
         // value: hex_to_bytes(
         // "08A20A0AFEF64124649232E0693C583AB1B9934AE63B4C3511F3AE1134C6A303EA3173BFEA6683BD101FA5AA5DBC1996FE7CACFC5A577D33EC14564CEC2BACBF",
@@ -341,16 +341,16 @@ pub fn test_vectors() -> Vec<TestVector> {
         // },
         // Test with invalid message length (17); valid test for BIP-340 post 2022.
         // TestVector {
-        // seckey: Some(PrivateKey::try_new(hex_to_bytes(
+        // seckey: PrivateKey::try_new(hex_to_bytes(
         // "0340034003400340034003400340034003400340034003400340034003400340",
         // )).unwrap()),
         // pubkey: PublicKey::try_new(hex_to_bytes(
         // "778CAA53B4393AC467774D09497A87224BF9FAB6F6E68B23086497324D6FD117",
         // )).unwrap(),
-        // aux_rand: Some(hex_to_bytes::<32>(
+        // aux_rand: hex_to_bytes::<32>(
         // "0000000000000000000000000000000000000000000000000000000000000000",
         // )),
-        // message: Some(hex::decode("0102030405060708090A0B0C0D0E0F1011").unwrap()),
+        // message: hex::decode("0102030405060708090A0B0C0D0E0F1011").unwrap()),
         // signature: Signature {
         // value: hex_to_bytes(
         // "5130F39A4059B43BC7CAC09A19ECE52B5D8699D1A71E3C52DA9AFDB6B50AC370C4A482B77BF960F8681540E25B6771ECE1E5A37FD80E5A51897C5566A97EA5A5",
@@ -360,16 +360,16 @@ pub fn test_vectors() -> Vec<TestVector> {
         // },
         // Test with invalid message length (100); valid test for BIP-340 post 2022.
         // TestVector {
-        // seckey: Some(PrivateKey::try_new(hex_to_bytes(
+        // seckey: PrivateKey::try_new(hex_to_bytes(
         // "0340034003400340034003400340034003400340034003400340034003400340",
         // )).unwrap()),
         // pubkey: PublicKey::try_new(hex_to_bytes(
         // "778CAA53B4393AC467774D09497A87224BF9FAB6F6E68B23086497324D6FD117",
         // )).unwrap(),
-        // aux_rand: Some(hex_to_bytes::<32>(
+        // aux_rand: hex_to_bytes::<32>(
         // "0000000000000000000000000000000000000000000000000000000000000000",
         // )),
-        // message: Some(
+        // message:
         // hex::decode("99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999").unwrap(),
         // ),
         // signature: Signature {
diff --git a/nssa/src/signature/mod.rs b/nssa/src/signature/mod.rs
index c96b315d..19daca2e 100644
--- a/nssa/src/signature/mod.rs
+++ b/nssa/src/signature/mod.rs
@@ -37,6 +37,8 @@ impl FromStr for Signature {
 
 impl Signature {
     #[must_use]
+    /// This function expects the incoming message to be prehashed to be pre-2022 BIP-340/Keycard
+    /// compatible.
     pub fn new(key: &PrivateKey, message: &[u8; 32]) -> Self {
         let mut aux_random = [0_u8; 32];
         OsRng.fill_bytes(&mut aux_random);
@@ -61,7 +63,7 @@ impl Signature {
     }
 
     #[must_use]
-    pub fn is_valid_for(&self, bytes: &[u8], public_key: &PublicKey) -> bool {
+    pub fn is_valid_for(&self, bytes: &[u8; 32], public_key: &PublicKey) -> bool {
         let Ok(pk) = k256::schnorr::VerifyingKey::from_bytes(public_key.value()) else {
             return false;
         };
@@ -97,9 +99,8 @@ mod tests {
             let Some(aux_random) = test_vector.aux_rand else {
                 continue;
             };
-            let Some(message) = test_vector.message else {
-                continue;
-            };
+            let message = test_vector.message;
+
             if !test_vector.verification_result {
                 continue;
             }
@@ -114,7 +115,7 @@ mod tests {
     #[test]
     fn signature_verification_from_bip340_test_vectors() {
         for (i, test_vector) in bip340_test_vectors::test_vectors().into_iter().enumerate() {
-            let message = test_vector.message.unwrap_or([0_u8; 32]);
+            let message = test_vector.message;
             let expected_result = test_vector.verification_result;
 
             let result = test_vector
diff --git a/wallet/src/lib.rs b/wallet/src/lib.rs
index 1362eed8..c86b2ae0 100644
--- a/wallet/src/lib.rs
+++ b/wallet/src/lib.rs
@@ -467,8 +467,7 @@ impl WalletCore {
             )
             .unwrap();
 
-        let witness_set = Self::sign_privacy_message(&message, &proof, &acc_manager, pin, key_path)
-            .expect("Expect a valid witness set");
+        let witness_set = Self::sign_privacy_message(&message, &proof, &acc_manager);
         let tx = PrivacyPreservingTransaction::new(message, witness_set);
 
         let shared_secrets: Vec<_> = private_account_keys