Statically return HDPrivateKey from HDPrivateKeys

peercoin · Aug 9, 2023 · 2fa9cf5 · 2fa9cf5
1 parent a2e73e2
commit 2fa9cf5
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Showing 3 changed files with 15 additions and 6 deletions.
diff --git a/coinlib/lib/src/crypto/hd_key.dart b/coinlib/lib/src/crypto/hd_key.dart
@@ -152,13 +152,13 @@ abstract class HDKey {
 
   /// Derives a hardened key at [index] which only applies to private keys. The
   /// [index] must not include the left-bit to specify that it is hardened.
-  HDKey deriveHardened(int index) {
+  HDPrivateKey deriveHardened(int index) {
     if (index < 0 || index >= hardenBit) {
       throw ArgumentError.value(
         index, "index", "should be below hardered index",
       );
     }
-    return derive(index + hardenBit);
+    return derive(index + hardenBit) as HDPrivateKey;
   }
 
   /// Derives a child key in a [path] format akin to "m/15/3'/4" where the
@@ -280,6 +280,12 @@ class HDPrivateKey extends HDKey {
     throw InvalidHDKey();
   }
 
+  @override
+  HDPrivateKey derive(int index) => super.derive(index) as HDPrivateKey;
+
+  @override
+  HDPrivateKey derivePath(String path) => super.derivePath(path) as HDPrivateKey;
+
   HDPublicKey get hdPublicKey => HDPublicKey(
     publicKey: publicKey,
     chaincode: chaincode,

diff --git a/coinlib/test/crypto/hd_key_test.dart b/coinlib/test/crypto/hd_key_test.dart
@@ -171,9 +171,9 @@ void main() {
       forEachHDVector((parent, vec) {
         if (parent != null) {
 
-          final derivedPriv = HDKey.decode(parent.privEncoded).derive(vec.index);
+          final derivedPriv = HDPrivateKey.decode(parent.privEncoded).derive(vec.index);
           expectPriv(derivedPriv);
-          vec.expectHDKey(derivedPriv);
+          vec.expectHDPrivateKey(derivedPriv);
 
           if (!vec.hardened) {
             final derivedPub = HDKey.decode(parent.pubEncoded).derive(vec.index);
@@ -191,7 +191,7 @@ void main() {
           final derivedHardened = HDKey.decode(parent.privEncoded)
             .deriveHardened(vec.index - 0x80000000);
           expectPriv(derivedHardened);
-          vec.expectHDKey(derivedHardened);
+          vec.expectHDPrivateKey(derivedHardened);
         }
       });
     });
@@ -201,7 +201,7 @@ void main() {
       final derived = masterHDKey.derivePath("m/0'/1/2'/2/1000000000");
 
       expectPriv(derived);
-      hdVectors[0][5].expectHDKey(derived);
+      hdVectors[0][5].expectHDPrivateKey(derived);
 
       final pubDerived = HDPublicKey.decode(hdVectors[0][3].pubEncoded, pubPrefix)
         .derivePath("2/1000000000");

diff --git a/coinlib/test/vectors/hd_keys.dart b/coinlib/test/vectors/hd_keys.dart
@@ -51,6 +51,9 @@ class HDVector {
 
   }
 
+  // Adds a static check to the key type
+  expectHDPrivateKey(HDPrivateKey key) => expectHDKey(key);
+
 }
 
 final hdVectors = [