Refactor key derivation

CHANGELOG.md

@@ -9,9 +9,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
  - `TRANSACTION_HAS_UNKNOWN_FIELDS` and `ACCOUNT_IS_IMMUTABLE` in `Status`
+ - `toStandard[Ed25519|ECDSAsecp256k1]PrivateKey()` to `Mnemonic`
+ - `fromSeed[ED25519|ECDSAsecp256k1]()` to `PrivateKey`
+ - `[PrivateKeyED25519|PrivateKeyECDSA].fromSeed()`
+ - `Bip32Utils` class
 
 ### Fixed
  - Misleading logging when an unhealthy node is hit
+ - ECDSA secp256k1 keys now support derivation
+
+### Deprecated
+ - `Mnemonic.toPrivateKey()` use `Mnemonic.toStandard[Ed25519|ECDSAsecp256k1]PrivateKey` instead
+ - `PrivateKey.fromMnemonic()` use `Mnemonic.toStandard[Ed25519|ECDSAsecp256k1]PrivateKey` instead
 
 ## 2.19.0
 

examples/src/main/java/GenerateKeyWithMnemonicExample.java

@@ -28,21 +28,11 @@ private GenerateKeyWithMnemonicExample() {
 
     public static void main(String[] args) {
         Mnemonic mnemonic = Mnemonic.generate24();
-        PrivateKey privateKey;
-        try {
-            privateKey = mnemonic.toPrivateKey();
-        } catch (BadMnemonicException e) {
-            throw new Error(e.reason.toString());
-        }
+        PrivateKey privateKey = mnemonic.toStandardEd25519PrivateKey("", 0);
         PublicKey publicKey = privateKey.getPublicKey();
 
         Mnemonic mnemonic12 = Mnemonic.generate12();
-        PrivateKey privateKey12;
-        try {
-            privateKey12 = mnemonic12.toPrivateKey();
-        } catch (BadMnemonicException e) {
-            throw new Error(e.reason.toString());
-        }
+        PrivateKey privateKey12 = mnemonic12.toStandardEd25519PrivateKey("", 0);
         PublicKey publicKey12 = privateKey12.getPublicKey();
 
         System.out.println("mnemonic 24 word = " + mnemonic);

sdk/src/main/java/com/hedera/hashgraph/sdk/Mnemonic.java

@@ -21,6 +21,7 @@
 
 import com.google.common.base.Joiner;
 import com.google.errorprone.annotations.Var;
+import com.hedera.hashgraph.sdk.utils.Bip32Utils;
 import org.bouncycastle.crypto.digests.SHA256Digest;
 import org.bouncycastle.crypto.digests.SHA512Digest;
 import org.bouncycastle.crypto.generators.PKCS5S2ParametersGenerator;
@@ -62,17 +63,11 @@ public final class Mnemonic {
      */
     public final List<CharSequence> words;
 
-    public boolean isLegacy = false;
-
     @Nullable
     private String asString;
 
     @SuppressWarnings("StaticAssignmentInConstructor")
     private Mnemonic(List<? extends CharSequence> words) {
-        if (words.size() == 22) {
-            isLegacy = true;
-        }
-
         this.words = Collections.unmodifiableList(words);
     }
 
@@ -317,24 +312,19 @@ private static boolean[] bytesToBits(byte[] dat) {
     }
 
     /**
+     * @deprecated use {@link #toStandardEd25519PrivateKey(String, int)} ()} or {@link #toStandardECDSAsecp256k1PrivateKey(String, int)} (String, int)} instead
      * Recover a private key from this mnemonic phrase.
      * <p>
      * This is not compatible with the phrases generated by the Android and iOS wallets;
      * use the no-passphrase version instead.
      *
-     * @param passphrase the passphrase used to protect the mnemonic (not used in the
-     *                   mobile wallets, use {@link #toPrivateKey()} instead.)
+     * @param passphrase the passphrase used to protect the mnemonic
      * @return the recovered key; use {@link PrivateKey#derive(int)} to get a
      * key for an account index (0 for default account)
      * @see PrivateKey#fromMnemonic(Mnemonic, String)
      */
-    public PrivateKey toPrivateKey(String passphrase) throws BadMnemonicException {
-        if (isLegacy) {
-            if (passphrase.compareTo("") != 0) {
-                throw new Error("Legacy mnemonic doesn't support passphrases");
-            }
-            return this.toLegacyPrivateKey();
-        }
+    @Deprecated
+    public PrivateKey toPrivateKey(String passphrase) {
         return PrivateKey.fromMnemonic(this, passphrase);
     }
 
@@ -353,6 +343,7 @@ public PrivateKey toLegacyPrivateKey() throws BadMnemonicException {
     }
 
     /**
+     * @deprecated use {@link #toStandardEd25519PrivateKey(String, int)} ()} or {@link #toStandardECDSAsecp256k1PrivateKey(String, int)} (String, int)} instead
      * Recover a private key from this mnemonic phrase.
      *
      * @return the recovered key; use
@@ -361,7 +352,8 @@ public PrivateKey toLegacyPrivateKey() throws BadMnemonicException {
      * default account)
      * @see PrivateKey#fromMnemonic(Mnemonic)
      */
-    public PrivateKey toPrivateKey() throws BadMnemonicException {
+    @Deprecated
+    public PrivateKey toPrivateKey() {
         return toPrivateKey("");
     }
 
@@ -448,7 +440,7 @@ private byte[] wordsToEntropyAndChecksum() {
         @Var int scratch = 0;
         @Var int offset = 0;
         for (CharSequence word : words) {
-            int index = getWordIndex(word, isLegacy);
+            int index = getWordIndex(word, false);
 
             if (index < 0) {
                 // should also be checked in `validate()`
@@ -476,10 +468,6 @@ private byte[] wordsToEntropyAndChecksum() {
     }
 
     private byte[] wordsToLegacyEntropy() throws BadMnemonicException {
-        if (!isLegacy) {
-            throw new BadMnemonicException(this, BadMnemonicReason.NotLegacy);
-        }
-
         var indices = new int[words.size()];
         for (var i = 0; i < words.size(); i++) {
             indices[i] = getWordIndex(words.get(i), true);
@@ -554,4 +542,48 @@ private byte[] wordsToLegacyEntropy2() throws BadMnemonicException {
 
         return entropy;
     }
+
+    /**
+     * Recover an Ed25519 private key from this mnemonic phrase, with an
+     * optional passphrase.
+     *
+     * @param passphrase    the passphrase used to protect the mnemonic
+     * @param index         the derivation index
+     * @return the private key
+     */
+    public PrivateKey toStandardEd25519PrivateKey(String passphrase, int index) {
+        var seed = this.toSeed(passphrase);
+        PrivateKey derivedKey = PrivateKey.fromSeedED25519(seed);
+
+        for (int i : new int[]{44, 3030, 0, 0, index}) {
+            derivedKey = derivedKey.derive(i);
+        }
+
+        return derivedKey;
+    }
+
+    /**
+     * Recover an ECDSAsecp256k1 private key from this mnemonic phrase, with an
+     * optional passphrase.
+     *
+     * @param passphrase    the passphrase used to protect the mnemonic
+     * @param index         the derivation index
+     * @return the private key
+     */
+    public PrivateKey toStandardECDSAsecp256k1PrivateKey(String passphrase, int index) {
+        var seed = this.toSeed(passphrase);
+        PrivateKey derivedKey = PrivateKey.fromSeedECDSAsecp256k1(seed);
+
+        // Harden the first 3 indexes
+        for (int i : new int[]{
+            Bip32Utils.toHardenedIndex(44),
+            Bip32Utils.toHardenedIndex(3030),
+            Bip32Utils.toHardenedIndex(0),
+            0,
+            index}) {
+            derivedKey = derivedKey.derive(i);
+        }
+
+        return derivedKey;
+    }
 }

sdk/src/main/java/com/hedera/hashgraph/sdk/PrivateKey.java

@@ -23,8 +23,6 @@
 import com.hedera.hashgraph.sdk.proto.SignedTransaction;
 import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
 import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
-import org.bouncycastle.crypto.digests.SHA512Digest;
-import org.bouncycastle.crypto.macs.HMac;
 import org.bouncycastle.crypto.params.KeyParameter;
 import org.bouncycastle.math.ec.rfc8032.Ed25519;
 import org.bouncycastle.util.encoders.Hex;
@@ -34,7 +32,6 @@
 import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
-import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 
 /**
@@ -75,6 +72,27 @@ public static PrivateKey generateECDSA() {
     }
 
     /**
+     * Extract the ED25519 private key from a seed.
+     *
+     * @param seed  the seed
+     * @return      the ED25519 private key
+     */
+    public static PrivateKey fromSeedED25519(byte[] seed) {
+        return PrivateKeyED25519.fromSeed(seed);
+    }
+
+    /**
+     * Extract the ECDSA private key from a seed.
+     *
+     * @param seed  the seed
+     * @return      the ECDSA private key
+     */
+    public static PrivateKey fromSeedECDSAsecp256k1(byte[] seed) {
+        return PrivateKeyECDSA.fromSeed(seed);
+    }
+
+    /**
+     * @deprecated use {@link Mnemonic#toStandardEd25519PrivateKey(String, int)} ()} or {@link Mnemonic#toStandardECDSAsecp256k1PrivateKey(String, int)} (String, int)} instead
      * Recover a private key from a generated mnemonic phrase and a passphrase.
      * <p>
      * This is not compatible with the phrases generated by the Android and iOS wallets;
@@ -86,17 +104,10 @@ public static PrivateKey generateECDSA() {
      * @return the recovered key; use {@link #derive(int)} to get a key for an account index (0
      * for default account)
      */
+    @Deprecated
     public static PrivateKey fromMnemonic(Mnemonic mnemonic, String passphrase) {
         var seed = mnemonic.toSeed(passphrase);
-
-        var hmacSha512 = new HMac(new SHA512Digest());
-        hmacSha512.init(new KeyParameter("ed25519 seed".getBytes(StandardCharsets.UTF_8)));
-        hmacSha512.update(seed, 0, seed.length);
-
-        var derivedState = new byte[hmacSha512.getMacSize()];
-        hmacSha512.doFinal(derivedState, 0);
-
-        @Var PrivateKey derivedKey = PrivateKeyED25519.derivableKeyED25519(derivedState);
+        @Var PrivateKey derivedKey = fromSeedED25519(seed);
 
         // BIP-44 path with the Hedera Hbar coin-type (omitting key index)
         // we pre-derive most of the path as the mobile wallets don't expose more than the index
@@ -110,6 +121,7 @@ public static PrivateKey fromMnemonic(Mnemonic mnemonic, String passphrase) {
     }
 
     /**
+     * @deprecated use {@link Mnemonic#toStandardEd25519PrivateKey(String, int)} ()} or {@link Mnemonic#toStandardECDSAsecp256k1PrivateKey(String, int)} (String, int)} instead
      * Recover a private key from a mnemonic phrase compatible with the iOS and Android wallets.
      * <p>
      * An overload of {@link #fromMnemonic(Mnemonic, String)} which uses an empty string for the
@@ -119,6 +131,7 @@ public static PrivateKey fromMnemonic(Mnemonic mnemonic, String passphrase) {
      * @return the recovered key; use {@link #derive(int)} to get a key for an account index (0
      * for default account)
      */
+    @Deprecated
     public static PrivateKey fromMnemonic(Mnemonic mnemonic) {
         return fromMnemonic(mnemonic, "");
     }
@@ -449,4 +462,6 @@ com.hedera.hashgraph.sdk.proto.Key toProtobufKey() {
      * @return                          are we an ECDSA key
      */
     public abstract boolean isECDSA();
+
+    public abstract KeyParameter getChainCode();
 }