wallet encryption with argon2 key derivation

src/main/java/com/sparrowwallet/drongo/crypto/Argon2KeyDeriver.java

@@ -6,34 +6,74 @@ import de.mkammerer.argon2.Argon2Factory;
 import java.nio.charset.StandardCharsets;
 import java.security.SecureRandom;
 
-public class Argon2KeyDeriver implements KeyDeriver {
+public class Argon2KeyDeriver implements KeyDeriver, AsymmetricKeyDeriver {
-    private static final int SALT_LENGTH = 16;
+    public static final Argon2Parameters TEST_PARAMETERS = new Argon2Parameters(16, 32, 1, 1024, 1);
-    private static final int HASH_LENGTH = 32;
+    public static final Argon2Parameters SPRW1_PARAMETERS = new Argon2Parameters(16, 32, 10, 256 * 1024, 4);
-    private static final int ITERATIONS = 10;
-    private static final int MEMORY = 256 * 1024;
-    private static final int PARALLELISM = 4;
 
+    private final Argon2Parameters argon2Parameters;
     private final byte[] salt;
 
     public Argon2KeyDeriver() {
+        this(isTest() ? TEST_PARAMETERS : SPRW1_PARAMETERS);
+    }
+
+    public Argon2KeyDeriver(Argon2Parameters argon2Parameters) {
+        this.argon2Parameters = argon2Parameters;
+
         SecureRandom secureRandom = new SecureRandom();
-        salt = new byte[SALT_LENGTH];
+        salt = new byte[argon2Parameters.saltLength];
         secureRandom.nextBytes(salt);
     }
 
     public Argon2KeyDeriver(byte[] salt) {
+        this(isTest() ? TEST_PARAMETERS : SPRW1_PARAMETERS, salt);
+    }
+
+    public Argon2KeyDeriver(Argon2Parameters argon2Parameters, byte[] salt) {
+        this.argon2Parameters = argon2Parameters;
         this.salt = salt;
     }
 
+    @Override
+    public byte[] getSalt() {
+        return salt;
+    }
+
     @Override
     public Key deriveKey(String password) throws KeyCrypterException {
-        Argon2Advanced argon2 = Argon2Factory.createAdvanced(Argon2Factory.Argon2Types.ARGON2id, SALT_LENGTH, HASH_LENGTH);
+        Argon2Advanced argon2 = Argon2Factory.createAdvanced(Argon2Factory.Argon2Types.ARGON2id, argon2Parameters.saltLength, argon2Parameters.hashLength);
-        byte[] hash = argon2.rawHash(ITERATIONS, MEMORY, PARALLELISM, password.getBytes(StandardCharsets.UTF_8), salt);
+        byte[] hash = argon2.rawHash(argon2Parameters.iterations, argon2Parameters.memory, argon2Parameters.parallelism, password.getBytes(StandardCharsets.UTF_8), salt);
         return new Key(hash, salt, getDeriverType());
     }
 
+    @Override
+    public ECKey deriveECKey(String password) throws KeyCrypterException {
+        Key key = deriveKey(password);
+        return ECKey.fromPrivate(key.getKeyBytes());
+    }
+
     @Override
     public EncryptionType.Deriver getDeriverType() {
         return EncryptionType.Deriver.ARGON2;
     }
+
+    private static boolean isTest() {
+        return System.getProperty("org.gradle.test.worker") != null;
+    }
+
+    public static class Argon2Parameters {
+        public final int saltLength;
+        public final int hashLength;
+        public final int iterations;
+        public final int memory;
+        public final int parallelism;
+
+        public Argon2Parameters(int saltLength, int hashLength, int iterations, int memory, int parallelism) {
+            this.saltLength = saltLength;
+            this.hashLength = hashLength;
+            this.iterations = iterations;
+            this.memory = memory;
+            this.parallelism = parallelism;
+        }
+    }
 }

src/main/java/com/sparrowwallet/drongo/crypto/AsymmetricKeyDeriver.java

@@ -8,4 +8,6 @@ public interface AsymmetricKeyDeriver {
      * @throws KeyCrypterException
      */
     ECKey deriveECKey(String password) throws KeyCrypterException;
+
+    byte[] getSalt();
 }

src/main/java/com/sparrowwallet/drongo/crypto/EncryptionType.java

@@ -49,6 +49,10 @@ public class EncryptionType {
             public KeyDeriver getKeyDeriver() {
                 return new Argon2KeyDeriver();
             }
+
+            public KeyDeriver getKeyDeriver(byte[] salt) {
+                return new Argon2KeyDeriver(salt);
+            }
         };
 
         public abstract KeyDeriver getKeyDeriver();

src/main/java/com/sparrowwallet/drongo/crypto/Pbkdf2KeyDeriver.java

@@ -29,6 +29,11 @@ public class Pbkdf2KeyDeriver implements KeyDeriver, AsymmetricKeyDeriver {
         this.iterationCount = iterationCount;
     }
 
+    @Override
+    public byte[] getSalt() {
+        return salt;
+    }
+
     @Override
     public Key deriveKey(String password) throws KeyCrypterException {
         PKCS5S2ParametersGenerator gen = new PKCS5S2ParametersGenerator(new SHA512Digest());

src/main/java/com/sparrowwallet/drongo/wallet/DeterministicSeed.java

@@ -158,7 +158,7 @@ public class DeterministicSeed implements EncryptableItem {
 
     @Override
     public EncryptionType getEncryptionType() {
-        return new EncryptionType(EncryptionType.Deriver.SCRYPT, EncryptionType.Crypter.AES_CBC_PKCS7);
+        return new EncryptionType(EncryptionType.Deriver.ARGON2, EncryptionType.Crypter.AES_CBC_PKCS7);
     }
 
     @Override
@@ -174,15 +174,13 @@ public class DeterministicSeed implements EncryptableItem {
         return type;
     }
 
-    public DeterministicSeed encrypt(String password) {
+    public DeterministicSeed encrypt(Key key) {
         if(encryptedMnemonicCode != null) {
             throw new IllegalArgumentException("Trying to encrypt twice");
         }
         if(mnemonicCode == null) {
             throw new IllegalArgumentException("Mnemonic missing so cannot encrypt");
         }
-        KeyDeriver keyDeriver = getEncryptionType().getDeriver().getKeyDeriver();
-        Key key = keyDeriver.deriveKey(password);
 
         KeyCrypter keyCrypter = getEncryptionType().getCrypter().getKeyCrypter();
         EncryptedData encryptedMnemonic = keyCrypter.encrypt(getMnemonicAsBytes(), null, key);
@@ -193,16 +191,30 @@ public class DeterministicSeed implements EncryptableItem {
     }
 
     private byte[] getMnemonicAsBytes() {
-        return getMnemonicString().getBytes(StandardCharsets.UTF_8);
+        String mnemonicString = getMnemonicString();
+        if(mnemonicString == null) {
+            return null;
+        }
+
+        return mnemonicString.getBytes(StandardCharsets.UTF_8);
     }
 
     public DeterministicSeed decrypt(String password) {
         if(!isEncrypted()) {
             throw new IllegalStateException("Cannot decrypt unencrypted seed");
         }
+
         KeyDeriver keyDeriver = getEncryptionType().getDeriver().getKeyDeriver(encryptedMnemonicCode.getKeySalt());
         Key key = keyDeriver.deriveKey(password);
 
+        return decrypt(key);
+    }
+
+    public DeterministicSeed decrypt(Key key) {
+        if(!isEncrypted()) {
+            throw new IllegalStateException("Cannot decrypt unencrypted seed");
+        }
+
         KeyCrypter keyCrypter = getEncryptionType().getCrypter().getKeyCrypter();
         List<String> mnemonic = decodeMnemonicCode(keyCrypter.decrypt(encryptedMnemonicCode, key));
         DeterministicSeed seed = new DeterministicSeed(mnemonic, needsPassphrase, creationTimeSeconds, type);

src/main/java/com/sparrowwallet/drongo/wallet/Keystore.java

@@ -185,15 +185,21 @@ public class Keystore {
         return seed != null && seed.isEncrypted();
     }
 
-    public void encrypt(String password) {
+    public void encrypt(Key key) {
-        if(seed != null && !seed.isEncrypted()) {
+        if(hasSeed() && !seed.isEncrypted()) {
-            seed = seed.encrypt(password);
+            seed = seed.encrypt(key);
         }
     }
 
     public void decrypt(String password) {
-        if(seed != null && seed.isEncrypted()) {
+        if(hasSeed() && seed.isEncrypted()) {
             seed = seed.decrypt(password);
         }
     }
+
+    public void decrypt(Key key) {
+        if(hasSeed() && seed.isEncrypted()) {
+            seed = seed.decrypt(key);
+        }
+    }
 }

src/main/java/com/sparrowwallet/drongo/wallet/Wallet.java

@@ -1,5 +1,6 @@
 package com.sparrowwallet.drongo.wallet;
 
+import com.sparrowwallet.drongo.crypto.Key;
 import com.sparrowwallet.drongo.policy.Policy;
 import com.sparrowwallet.drongo.policy.PolicyType;
 import com.sparrowwallet.drongo.protocol.ScriptType;
@@ -156,9 +157,9 @@ public class Wallet {
         return false;
     }
 
-    public void encrypt(String password) {
+    public void encrypt(Key key) {
         for(Keystore keystore : keystores) {
-            keystore.encrypt(password);
+            keystore.encrypt(key);
         }
     }
 
@@ -167,4 +168,10 @@ public class Wallet {
             keystore.decrypt(password);
         }
     }
+
+    public void decrypt(Key key) {
+        for(Keystore keystore : keystores) {
+            keystore.decrypt(key);
+        }
+    }
 }

src/test/java/com/sparrowwallet/drongo/crypto/Argon2KeyDeriverTest.java

@@ -1,8 +1,6 @@
 package com.sparrowwallet.drongo.crypto;
 
-import de.mkammerer.argon2.Argon2;
+import com.sparrowwallet.drongo.Utils;
-import de.mkammerer.argon2.Argon2Factory;
-import de.mkammerer.argon2.Argon2Helper;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -10,11 +8,24 @@ import java.nio.charset.StandardCharsets;
 import java.security.SecureRandom;
 
 public class Argon2KeyDeriverTest {
+    @Test
+    public void noPasswordTest() {
+        String password = "";
+
+        Argon2KeyDeriver.Argon2Parameters testParams = Argon2KeyDeriver.TEST_PARAMETERS;
+        byte[] salt = new byte[testParams.saltLength];
+        Argon2KeyDeriver keyDeriver = new Argon2KeyDeriver(salt);
+        Key key = keyDeriver.deriveKey(password);
+
+        String hex = Utils.bytesToHex(key.getKeyBytes());
+        Assert.assertEquals("6f6600a054c0271b96788906f62dfb1323c37b761715a0ae95ac524e4e1f2811", hex);
+    }
+
     @Test
     public void testArgon2() {
         String password = "thisisapassword";
 
-        Argon2KeyDeriver keyDeriver = new Argon2KeyDeriver();
+        Argon2KeyDeriver keyDeriver = new Argon2KeyDeriver(Argon2KeyDeriver.TEST_PARAMETERS);
         Key key = keyDeriver.deriveKey(password);
 
         KeyCrypter keyCrypter = new AESKeyCrypter();
@@ -30,7 +41,7 @@ public class Argon2KeyDeriverTest {
 
         //Decrypt
 
-        Argon2KeyDeriver keyDeriver2 = new Argon2KeyDeriver(encrypted.getKeySalt());
+        Argon2KeyDeriver keyDeriver2 = new Argon2KeyDeriver(Argon2KeyDeriver.TEST_PARAMETERS, encrypted.getKeySalt());
         Key key2 = keyDeriver2.deriveKey(password);
 
         byte[] decrypted = keyCrypter.decrypt(encrypted, key2);

src/test/java/com/sparrowwallet/drongo/wallet/DeterministicSeedTest.java

@@ -1,6 +1,6 @@
 package com.sparrowwallet.drongo.wallet;
 
-import com.sparrowwallet.drongo.Utils;
+import com.sparrowwallet.drongo.crypto.KeyDeriver;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -10,7 +10,8 @@ public class DeterministicSeedTest {
         String words = "absent essay fox snake vast pumpkin height crouch silent bulb excuse razor";
 
         DeterministicSeed seed = new DeterministicSeed(words, "pp", 0, DeterministicSeed.Type.BIP39);
-        DeterministicSeed encryptedSeed = seed.encrypt("pass");
+        KeyDeriver keyDeriver = seed.getEncryptionType().getDeriver().getKeyDeriver();
+        DeterministicSeed encryptedSeed = seed.encrypt(keyDeriver.deriveKey("pass"));
 
         DeterministicSeed decryptedSeed = encryptedSeed.decrypt("pass");
         Assert.assertEquals(words, decryptedSeed.getMnemonicString());

src/test/java/com/sparrowwallet/drongo/wallet/WalletTest.java

@@ -1,5 +1,8 @@
 package com.sparrowwallet.drongo.wallet;
 
+import com.sparrowwallet.drongo.crypto.Argon2KeyDeriver;
+import com.sparrowwallet.drongo.crypto.Key;
+import com.sparrowwallet.drongo.crypto.KeyDeriver;
 import com.sparrowwallet.drongo.policy.Policy;
 import com.sparrowwallet.drongo.policy.PolicyType;
 import com.sparrowwallet.drongo.protocol.ScriptType;
@@ -17,7 +20,10 @@ public class WalletTest {
         wallet.getKeystores().add(keystore);
         wallet.setDefaultPolicy(Policy.getPolicy(PolicyType.SINGLE, ScriptType.P2PKH, wallet.getKeystores(), 1));
 
-        wallet.encrypt("pass");
+        KeyDeriver keyDeriver = new Argon2KeyDeriver();
+        Key key = keyDeriver.deriveKey("pass");
+        wallet.encrypt(key);
+
         wallet.decrypt("pass");
     }
 }