1 files changed, 149 insertions, 0 deletions
diff --git a/core/src/test/java/org/spongycastle/crypto/ec/test/ECTransformationTest.java b/core/src/test/java/org/spongycastle/crypto/ec/test/ECTransformationTest.java
new file mode 100644
index 00000000..3b6e64e1
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+++ b/core/src/test/java/org/spongycastle/crypto/ec/test/ECTransformationTest.java
@@ -0,0 +1,149 @@
+package org.spongycastle.crypto.ec.test;
+
+import java.math.BigInteger;
+import java.security.SecureRandom;
+
+import org.spongycastle.crypto.AsymmetricCipherKeyPair;
+import org.spongycastle.crypto.ec.ECDecryptor;
+import org.spongycastle.crypto.ec.ECElGamalDecryptor;
+import org.spongycastle.crypto.ec.ECElGamalEncryptor;
+import org.spongycastle.crypto.ec.ECEncryptor;
+import org.spongycastle.crypto.ec.ECNewPublicKeyTransform;
+import org.spongycastle.crypto.ec.ECNewRandomnessTransform;
+import org.spongycastle.crypto.ec.ECPair;
+import org.spongycastle.crypto.ec.ECPairTransform;
+import org.spongycastle.crypto.generators.ECKeyPairGenerator;
+import org.spongycastle.crypto.params.ECDomainParameters;
+import org.spongycastle.crypto.params.ECKeyGenerationParameters;
+import org.spongycastle.crypto.params.ECPrivateKeyParameters;
+import org.spongycastle.crypto.params.ECPublicKeyParameters;
+import org.spongycastle.crypto.params.ParametersWithRandom;
+import org.spongycastle.math.ec.ECConstants;
+import org.spongycastle.math.ec.ECCurve;
+import org.spongycastle.math.ec.ECPoint;
+import org.spongycastle.util.encoders.Hex;
+import org.spongycastle.util.test.SimpleTest;
+
+public class ECTransformationTest
+    extends SimpleTest
+{
+    public String getName()
+    {
+        return "ECTransformationTest";
+    }
+
+    public void performTest()
+        throws Exception
+    {
+        BigInteger n = new BigInteger("6277101735386680763835789423176059013767194773182842284081");
+
+        ECCurve.Fp curve = new ECCurve.Fp(
+            new BigInteger("6277101735386680763835789423207666416083908700390324961279"), // q
+            new BigInteger("fffffffffffffffffffffffffffffffefffffffffffffffc", 16), // a
+            new BigInteger("64210519e59c80e70fa7e9ab72243049feb8deecc146b9b1", 16), // b
+            n, ECConstants.ONE);
+
+        ECDomainParameters params = new ECDomainParameters(
+                curve,
+                curve.decodePoint(Hex.decode("03188da80eb03090f67cbf20eb43a18800f4ff0afd82ff1012")), // G
+                n);
+
+        ECPublicKeyParameters pubKey = new ECPublicKeyParameters(
+                    curve.decodePoint(Hex.decode("0262b12d60690cdcf330babab6e69763b471f994dd702d16a5")), // Q
+                    params);
+
+        ECPrivateKeyParameters priKey = new ECPrivateKeyParameters(
+            new BigInteger("651056770906015076056810763456358567190100156695615665659"), // d
+            params);
+
+
+        ParametersWithRandom pRandom = new ParametersWithRandom(pubKey, new SecureRandom());
+
+        doTest(priKey, pRandom, BigInteger.valueOf(20));
+
+        BigInteger rand = new BigInteger(pubKey.getParameters().getN().bitLength() - 1, new SecureRandom());
+
+        doTest(priKey, pRandom, rand);
+        doSameKeyTest(priKey, pRandom, rand);
+    }
+
+    private void doTest(ECPrivateKeyParameters priKey, ParametersWithRandom pRandom, BigInteger value)
+    {
+        ECPoint data = priKey.getParameters().getG().multiply(value);
+
+        ECEncryptor encryptor = new ECElGamalEncryptor();
+
+        encryptor.init(pRandom);
+
+        ECPair pair = encryptor.encrypt(data);
+
+        ECKeyPairGenerator ecGen = new ECKeyPairGenerator();
+
+        ecGen.init(new ECKeyGenerationParameters(priKey.getParameters(), new SecureRandom()));
+
+        AsymmetricCipherKeyPair reEncKP = ecGen.generateKeyPair();
+
+        ECPairTransform ecr = new ECNewPublicKeyTransform();
+
+        ecr.init(reEncKP.getPublic());
+
+        ECPair srcPair = pair;
+
+        // re-encrypt the message portion
+        pair = ecr.transform(srcPair);
+
+        ECDecryptor decryptor = new ECElGamalDecryptor();
+
+        decryptor.init(priKey);
+
+        // decrypt out the original private key
+        ECPoint p = decryptor.decrypt(new ECPair(srcPair.getX(), pair.getY()));
+
+        decryptor.init(reEncKP.getPrivate());
+
+        // decrypt the fully transformed point.
+        ECPoint result = decryptor.decrypt(new ECPair(pair.getX(), p));
+
+        if (!data.equals(result))
+        {
+            fail("point pair failed to decrypt back to original");
+        }
+    }
+
+    private void doSameKeyTest(ECPrivateKeyParameters priKey, ParametersWithRandom pRandom, BigInteger value)
+    {
+        ECPoint data = priKey.getParameters().getG().multiply(value);
+
+        ECEncryptor encryptor = new ECElGamalEncryptor();
+
+        encryptor.init(pRandom);
+
+        ECPair pair = encryptor.encrypt(data);
+
+        ECPairTransform ecr = new ECNewRandomnessTransform();
+
+        ecr.init(pRandom);
+
+        ECPair srcPair = pair;
+
+        // re-encrypt the message portion
+        pair = ecr.transform(srcPair);
+
+        ECDecryptor decryptor = new ECElGamalDecryptor();
+
+        decryptor.init(priKey);
+
+        // decrypt the fully transformed point.
+        ECPoint result = decryptor.decrypt(pair);
+
+        if (!data.equals(result))
+        {
+            fail("point pair failed to decrypt back to original");
+        }
+    }
+
+    public static void main(String[] args)
+    {
+        runTest(new ECTransformationTest());
+    }
+}