add argon2 key deriver

build.gradle

@@ -44,6 +44,10 @@ dependencies {
     implementation ('org.bouncycastle:bcprov-jdk15on:1.64') {
         exclude group: 'org.hamcrest', module: 'hamcrest-core'
     }
+    implementation ('de.mkammerer:argon2-jvm:2.7') {
+        exclude group: 'org.hamcrest', module: 'hamcrest-core'
+        exclude group: 'junit', module: 'junit'
+    }
     implementation ('ch.qos.logback:logback-classic:1.2.3') {
         exclude group: 'org.hamcrest', module: 'hamcrest-core'
     }

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

@@ -1,9 +1,35 @@
 package com.sparrowwallet.drongo.crypto;
 
+import de.mkammerer.argon2.Argon2Advanced;
+import de.mkammerer.argon2.Argon2Factory;
+
+import java.nio.charset.StandardCharsets;
+import java.security.SecureRandom;
+
 public class Argon2KeyDeriver implements KeyDeriver {
+    private static final int SALT_LENGTH = 16;
+    private static final int HASH_LENGTH = 32;
+    private static final int ITERATIONS = 10;
+    private static final int MEMORY = 256 * 1024;
+    private static final int PARALLELISM = 4;
+
+    private final byte[] salt;
+
+    public Argon2KeyDeriver() {
+        SecureRandom secureRandom = new SecureRandom();
+        salt = new byte[SALT_LENGTH];
+        secureRandom.nextBytes(salt);
+    }
+
+    public Argon2KeyDeriver(byte[] salt) {
+        this.salt = salt;
+    }
+
     @Override
     public Key deriveKey(String password) throws KeyCrypterException {
-        return null;
+        Argon2Advanced argon2 = Argon2Factory.createAdvanced(Argon2Factory.Argon2Types.ARGON2id, SALT_LENGTH, HASH_LENGTH);
+        byte[] hash = argon2.rawHash(ITERATIONS, MEMORY, PARALLELISM, password.getBytes(StandardCharsets.UTF_8), salt);
+        return new Key(hash, salt, getDeriverType());
     }
 
     @Override

src/main/java/module-info.java

@@ -1,5 +1,6 @@
 open module com.sparrowwallet.drongo {
     requires org.bouncycastle.provider;
+    requires de.mkammerer.argon2;
     requires slf4j.api;
     exports com.sparrowwallet.drongo;
     exports com.sparrowwallet.drongo.psbt;

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

@@ -0,0 +1,52 @@
+package com.sparrowwallet.drongo.crypto;
+
+import de.mkammerer.argon2.Argon2;
+import de.mkammerer.argon2.Argon2Factory;
+import de.mkammerer.argon2.Argon2Helper;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.nio.charset.StandardCharsets;
+import java.security.SecureRandom;
+
+public class Argon2KeyDeriverTest {
+    @Test
+    public void testArgon2() {
+        String password = "thisisapassword";
+
+        Argon2KeyDeriver keyDeriver = new Argon2KeyDeriver();
+        Key key = keyDeriver.deriveKey(password);
+
+        KeyCrypter keyCrypter = new AESKeyCrypter();
+
+        String message = "absent essay fox snake vast pumpkin height crouch silent bulb excuse razor";
+        byte[] messageBytes = message.getBytes(StandardCharsets.UTF_8);
+
+        byte[] iv = new byte[16];
+        SecureRandom secureRandom = new SecureRandom();
+        secureRandom.nextBytes(iv);
+
+        EncryptedData encrypted = keyCrypter.encrypt(messageBytes, iv, key);
+
+        //Decrypt
+
+        Argon2KeyDeriver keyDeriver2 = new Argon2KeyDeriver(encrypted.getKeySalt());
+        Key key2 = keyDeriver2.deriveKey(password);
+
+        byte[] decrypted = keyCrypter.decrypt(encrypted, key2);
+        String decryptedMessage = new String(decrypted, StandardCharsets.UTF_8);
+
+        Assert.assertEquals(message, decryptedMessage);
+    }
+
+//    @Test
+//    public void findIterations() {
+//        Argon2 argon2 = Argon2Factory.create();
+//        // 1000 = The hash call must take at most 1000 ms
+//        // 65536 = Memory cost
+//        // 1 = parallelism
+//        int iterations = Argon2Helper.findIterations(argon2, 500, 256*1024, 4);
+//
+//        System.out.println("Optimal number of iterations: " + iterations);
+//    }
+}