test(wallet-core): add property-based SEP-0005 derivation coverage

Cargo.toml

@@ -58,6 +58,7 @@ anyhow = "1"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 rand = "0.8"
+proptest = "1"
 
 # --- internal crates ---
 octo-crypto = { path = "crates/crypto" }

crates/wallet-core/Cargo.toml

@@ -22,3 +22,4 @@ hex.workspace = true
 sha2.workspace = true
 
 [dev-dependencies]
+proptest = { workspace = true }

crates/wallet-core/src/derive.rs

@@ -71,6 +71,7 @@ impl WalletSeed {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use proptest::prelude::*;
     use stellar_strkey::ed25519::PublicKey;
 
     // Official SEP-0005 Test 1 vector (no passphrase).
@@ -122,4 +123,53 @@ mod tests {
             Err(WalletError::InvalidMnemonic)
         ));
     }
+
+    proptest! {
+        #[test]
+        fn derivation_is_deterministic_for_any_index(
+            entropy in any::<[u8; 16]>(),
+            index in any::<u32>()
+        ) {
+            let mnemonic =
+                bip39::Mnemonic::from_entropy(&entropy, bip39::Language::English).unwrap();
+            let seed_bytes = bip39::Seed::new(&mnemonic, "").as_bytes().to_vec();
+            let seed_a = WalletSeed::from_bytes(seed_bytes.clone());
+            let seed_b = WalletSeed::from_bytes(seed_bytes);
+            let secret_a = seed_a.derive_ed25519_secret(index);
+            let secret_b = seed_b.derive_ed25519_secret(index);
+            prop_assert_eq!(*secret_a, *secret_b);
+        }
+
+        #[test]
+        fn distinct_indices_yield_distinct_secrets(
+            entropy in any::<[u8; 16]>(),
+            index_a in any::<u32>(),
+            index_b in any::<u32>()
+        ) {
+            prop_assume!(index_a != index_b);
+            let mnemonic =
+                bip39::Mnemonic::from_entropy(&entropy, bip39::Language::English).unwrap();
+            let seed =
+                WalletSeed::from_bytes(bip39::Seed::new(&mnemonic, "").as_bytes().to_vec());
+            let secret_a = seed.derive_ed25519_secret(index_a);
+            let secret_b = seed.derive_ed25519_secret(index_b);
+            prop_assert_ne!(*secret_a, *secret_b);
+        }
+    }
+
+    #[test]
+    fn boundary_indices_derive_without_panic() {
+        let seed = WalletSeed::from_phrase(VECTOR_MNEMONIC).unwrap();
+        // Exercises the hardened-offset OR-mask at the extreme ends of u32:
+        // 0, 1 (lowest valid indices), HARDENED-1 (highest non-hardened u32 value),
+        // and u32::MAX (wraps the OR-mask into the already-set upper bit).
+        for &index in &[0u32, 1, super::HARDENED - 1, u32::MAX] {
+            let secret = seed.derive_ed25519_secret(index);
+            let signing = ed25519_dalek::SigningKey::from_bytes(&secret);
+            let pk = PublicKey(signing.verifying_key().to_bytes());
+            let encoded = format!("{pk}");
+            let decoded = PublicKey::from_string(&encoded).unwrap();
+            assert_eq!(decoded.0, signing.verifying_key().to_bytes());
+        }
+    }
 }

crates/wallet-core/src/signer.rs

@@ -590,7 +590,7 @@ mod tests {
             &sealed,
             StellarNetwork::Testnet,
             0,
-            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200, sequence: 0 },
+            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200 },
         )
         .unwrap();
 
@@ -631,7 +631,7 @@ mod tests {
             &sealed,
             StellarNetwork::Testnet,
             0,
-            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200, sequence: 0 },
+            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200 },
         )
         .unwrap();
 
@@ -658,7 +658,7 @@ mod tests {
             &sealed,
             StellarNetwork::Testnet,
             0,
-            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200, sequence: 0 },
+            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200 },
         )
         .unwrap();
 
@@ -682,7 +682,7 @@ mod tests {
                 &sealed,
                 StellarNetwork::Testnet,
                 0,
-                &FeeBumpRequest { inner_xdr: "", max_base_fee_stroops: 200, sequence: 0 },
+                &FeeBumpRequest { inner_xdr: "", max_base_fee_stroops: 200 },
             ),
             Err(WalletError::InvalidXdr)
         ));
@@ -701,7 +701,7 @@ mod tests {
             &sealed,
             StellarNetwork::Testnet,
             0,
-            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200, sequence: 0 },
+            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200 },
         )
         .unwrap()
         .envelope_xdr;
@@ -713,7 +713,7 @@ mod tests {
                 &sealed,
                 StellarNetwork::Testnet,
                 0,
-                &FeeBumpRequest { inner_xdr: &fee_bump_xdr, max_base_fee_stroops: 200, sequence: 0 },
+                &FeeBumpRequest { inner_xdr: &fee_bump_xdr, max_base_fee_stroops: 200 },
             ),
             Err(WalletError::InvalidXdr)
         ));
@@ -731,7 +731,7 @@ mod tests {
                 &mainnet_sealed,
                 StellarNetwork::Testnet,
                 0,
-                &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200, sequence: 0 },
+                &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200 },
             ),
             Err(WalletError::SeedDecryption)
         ));
@@ -750,7 +750,7 @@ mod tests {
             &sealed,
             StellarNetwork::Testnet,
             0,
-            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: max_base_fee, sequence: 0 },
+            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: max_base_fee },
         )
         .unwrap();
 
@@ -776,7 +776,7 @@ mod tests {
             &sealed,
             StellarNetwork::Testnet,
             0,
-            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200, sequence: 0 },
+            &FeeBumpRequest { inner_xdr: &inner_xdr, max_base_fee_stroops: 200 },
         );
         assert!(result.is_ok());
         assert_eq!(result.unwrap().source_account, MASTER_ACCOUNT_0);