Introduce Coder/Decoder for ECIES

ethereumj-core/src/main/java/org/ethereum/crypto/ECIESCoder.java

@@ -0,0 +1,120 @@
+package org.ethereum.crypto;
+
+import org.ethereum.ConcatKDFBytesGenerator;
+import org.spongycastle.crypto.AsymmetricCipherKeyPair;
+import org.spongycastle.crypto.BufferedBlockCipher;
+import org.spongycastle.crypto.InvalidCipherTextException;
+import org.spongycastle.crypto.KeyGenerationParameters;
+import org.spongycastle.crypto.agreement.ECDHBasicAgreement;
+import org.spongycastle.crypto.digests.SHA256Digest;
+import org.spongycastle.crypto.engines.AESFastEngine;
+import org.spongycastle.crypto.generators.ECKeyPairGenerator;
+import org.spongycastle.crypto.generators.KDF2BytesGenerator;
+import org.spongycastle.crypto.macs.HMac;
+import org.spongycastle.crypto.modes.SICBlockCipher;
+import org.spongycastle.crypto.params.*;
+import org.spongycastle.math.ec.ECPoint;
+
+import java.io.ByteArrayInputStream;
+import java.math.BigInteger;
+import java.security.SecureRandom;
+
+import static org.ethereum.crypto.ECKey.CURVE;
+
+public class ECIESCoder {
+
+
+    public static final int MAC_KEY_SIZE = 128;
+
+
+    public static byte[] decrypt(BigInteger privKey, byte[] cipher) {
+
+        byte[] plaintext = new byte[0];
+        try {
+            ByteArrayInputStream is = new ByteArrayInputStream(cipher);
+            byte[] ephemBytes = new byte[2*((CURVE.getCurve().getFieldSize()+7)/8) + 1];
+            is.read(ephemBytes);
+            ECPoint ephem = CURVE.getCurve().decodePoint(ephemBytes);
+            byte[] IV = new byte[MAC_KEY_SIZE/8];
+            is.read(IV);
+            byte[] cipherBody = new byte[is.available()];
+            is.read(cipherBody);
+
+            plaintext = decrypt(ephem, privKey, IV, cipherBody);
+        } catch (Throwable throwable) {
+            throwable.printStackTrace();
+        }
+
+        return plaintext;
+    }
+
+    public static byte[] decrypt(ECPoint ephem, BigInteger prv, byte[] IV, byte[] cipher) throws Throwable {
+        AESFastEngine aesFastEngine = new AESFastEngine();
+
+        EthereumIESEngine iesEngine = new EthereumIESEngine(
+                new ECDHBasicAgreement(),
+                new ConcatKDFBytesGenerator(new SHA256Digest()),
+                new HMac(new SHA256Digest()),
+                new SHA256Digest(),
+                new BufferedBlockCipher(new SICBlockCipher(aesFastEngine)));
+
+
+        byte[]         d = new byte[] {};
+        byte[]         e = new byte[] {};
+
+        IESParameters p = new IESWithCipherParameters(d, e, MAC_KEY_SIZE, MAC_KEY_SIZE);
+        ParametersWithIV parametersWithIV =
+                new ParametersWithIV(p, IV);
+
+        iesEngine.init(false, new ECPrivateKeyParameters(prv, CURVE), new ECPublicKeyParameters(ephem, CURVE), parametersWithIV);
+
+        byte[] message = iesEngine.processBlock(cipher, 0, cipher.length);
+        return message;
+    }
+
+
+    public static byte[] encrypt(byte[] plaintext) {
+        AESFastEngine aesFastEngine = new AESFastEngine();
+
+        EthereumIESEngine iesEngine = new EthereumIESEngine(
+                new ECDHBasicAgreement(),
+                new KDF2BytesGenerator(new SHA256Digest()),
+                new HMac(new SHA256Digest()),
+                new SHA256Digest(),
+                new BufferedBlockCipher(new SICBlockCipher(aesFastEngine)));
+
+
+        byte[]         d = new byte[] {};
+        byte[]         e = new byte[] {};
+
+        IESParameters p = new IESWithCipherParameters(d, e, 256, MAC_KEY_SIZE);
+        ParametersWithIV parametersWithIV = new ParametersWithIV(p, new byte[256/8]);
+
+        ECKeyPairGenerator eGen = new ECKeyPairGenerator();
+        SecureRandom random = new SecureRandom();
+        KeyGenerationParameters gParam = new ECKeyGenerationParameters(CURVE, random);
+
+        eGen.init(gParam);
+
+
+        AsymmetricCipherKeyPair p1 = eGen.generateKeyPair();
+        AsymmetricCipherKeyPair p2 = eGen.generateKeyPair();
+
+
+        ECKeyGenerationParameters keygenParams = new ECKeyGenerationParameters(CURVE, random);
+        ECKeyPairGenerator generator = new ECKeyPairGenerator();
+        generator.init(keygenParams);
+
+        ECKeyPairGenerator gen = new ECKeyPairGenerator();
+        gen.init(new ECKeyGenerationParameters(CURVE, random));
+
+        iesEngine.init(true, p1.getPrivate(), p2.getPublic(), parametersWithIV);
+
+        byte[] cipher = new byte[0];
+        try {
+            cipher = iesEngine.processBlock(plaintext, 0, plaintext.length);
+        } catch (InvalidCipherTextException e1) {e1.printStackTrace();}
+        return cipher;
+    }
+
+}

ethereumj-core/src/test/java/test/ethereum/crypto/ECIESCoderTest.java

@@ -0,0 +1,33 @@
+package test.ethereum.crypto;
+
+import org.ethereum.crypto.ECIESCoder;
+import org.junit.Assert;
+import org.junit.Test;
+import org.spongycastle.util.encoders.Hex;
+
+import java.math.BigInteger;
+
+public class ECIESCoderTest {
+
+
+    @Test // decrypt cpp data
+    public void test1(){
+        BigInteger privKey = new BigInteger("5e173f6ac3c669587538e7727cf19b782a4f2fda07c1eaa662c593e5e85e3051", 16);
+        byte[] cipher = Hex.decode("049934a7b2d7f9af8fd9db941d9da281ac9381b5740e1f64f7092f3588d4f87f5ce55191a6653e5e80c1c5dd538169aa123e70dc6ffc5af1827e546c0e958e42dad355bcc1fcb9cdf2cf47ff524d2ad98cbf275e661bf4cf00960e74b5956b799771334f426df007350b46049adb21a6e78ab1408d5e6ccde6fb5e69f0f4c92bb9c725c02f99fa72b9cdc8dd53cff089e0e73317f61cc5abf6152513cb7d833f09d2851603919bf0fbe44d79a09245c6e8338eb502083dc84b846f2fee1cc310d2cc8b1b9334728f97220bb799376233e113");
+        byte[] payload = ECIESCoder.decrypt(privKey, cipher);
+
+
+        Assert.assertEquals("802b052f8b066640bba94a4fc39d63815c377fced6fcb84d27f791c9921ddf3e9bf0108e298f490812847109cbd778fae393e80323fd643209841a3b7f110397f37ec61d84cea03dcc5e8385db93248584e8af4b4d1c832d8c7453c0089687a700",
+                Hex.toHexString(payload));
+    }
+
+
+    @Test
+    public void test2(){
+
+        byte[] output = ECIESCoder.encrypt("roman".getBytes());
+        System.out.println(Hex.toHexString(output));
+
+    }
+
+}

ethereumj-core/src/test/java/test/ethereum/crypto/ECIESTest.java

@@ -140,4 +140,5 @@ public class ECIESTest {
         byte[] cipher = iesEngine.processBlock(plaintext, 0, plaintext.length);
         return cipher;
     }
+
 }