Reverse the sense of 'forEncryption'

Remove debug output from test
Improve SecureRandom usage

2 files changed, 35 insertions, 36 deletions

diff --git a/core/src/main/java/org/bouncycastle/crypto/engines/CramerShoupCoreEngine.java b/core/src/main/java/org/bouncycastle/crypto/engines/CramerShoupCoreEngine.java
index 71cab278..cc6d96be 100644
--- a/core/src/main/java/org/bouncycastle/crypto/engines/CramerShoupCoreEngine.java
+++ b/core/src/main/java/org/bouncycastle/crypto/engines/CramerShoupCoreEngine.java
@@ -23,43 +23,48 @@ public class CramerShoupCoreEngine {
 	private static final BigInteger ONE = BigInteger.ONE;
 	
 	private CramerShoupKeyParameters key;
+    private SecureRandom random;
 	private boolean forEncryption;
 	private String label = null;
 
 	/**
 	 * initialise the CramerShoup engine.
 	 * 
-	 * @param enc
+	 * @param forEncryption
 	 *            	whether this engine should encrypt or decrypt
 	 * @param param
 	 *            	the necessary CramerShoup key parameters.
 	 * @param label
 	 * 				the label for labelled CS as {@link String}
 	 */
-	public void init(boolean enc, CipherParameters param, String label) {
-		init(enc, param);
+	public void init(boolean forEncryption, CipherParameters param, String label) {
+		init(forEncryption, param);
 		
 		this.label = label;
 	}
-	
+
 	/**
 	 * initialise the CramerShoup engine.
 	 * 
-	 * @param enc
+	 * @param forEncryption
 	 *            whether this engine should encrypt or decrypt
 	 * @param param
 	 *            the necessary CramerShoup key parameters.
 	 */
-	public void init(boolean enc, CipherParameters param) {
+	public void init(boolean forEncryption, CipherParameters param) {
+        SecureRandom providedRandom = null;
+
 		if (param instanceof ParametersWithRandom) {
 			ParametersWithRandom rParam = (ParametersWithRandom) param;
 
 			key = (CramerShoupKeyParameters) rParam.getParameters();
+            providedRandom = rParam.getRandom();
 		} else {
 			key = (CramerShoupKeyParameters) param;
 		}
 
-		this.forEncryption = enc;
+        this.random = initSecureRandom(forEncryption, providedRandom);
+		this.forEncryption = forEncryption;
 	}
 
 	/**
@@ -103,7 +108,7 @@ public class CramerShoupCoreEngine {
 	public BigInteger convertInput(byte[] in, int inOff, int inLen) {
 		if (inLen > (getInputBlockSize() + 1)) {
 			throw new DataLengthException("input too large for Cramer Shoup cipher.");
-		} else if (inLen == (getInputBlockSize() + 1) && !forEncryption) {
+		} else if (inLen == (getInputBlockSize() + 1) && forEncryption) {
 			throw new DataLengthException("input too large for Cramer Shoup cipher.");
 		}
 
@@ -128,7 +133,7 @@ public class CramerShoupCoreEngine {
 	public byte[] convertOutput(BigInteger result) {
 		byte[] output = result.toByteArray();
 
-		if (forEncryption) {
+		if (!forEncryption) {
 			if (output[0] == 0 && output.length > getOutputBlockSize()) { // have ended up with an extra zero byte, copy down.
 				byte[] tmp = new byte[output.length - 1];
 
@@ -160,9 +165,8 @@ public class CramerShoupCoreEngine {
 	public CramerShoupCiphertext encryptBlock(BigInteger input) {
 
 		CramerShoupCiphertext result = null;
-		
 
-		if (!key.isPrivate() && !this.forEncryption && key instanceof CramerShoupPublicKeyParameters) {
+		if (!key.isPrivate() && this.forEncryption && key instanceof CramerShoupPublicKeyParameters) {
 			CramerShoupPublicKeyParameters pk = (CramerShoupPublicKeyParameters)key;
 			BigInteger p = pk.getParameters().getP();
 			BigInteger g1 = pk.getParameters().getG1();
@@ -173,7 +177,7 @@ public class CramerShoupCoreEngine {
 			if (!isValidMessage(input, p))
 				return result;
 			
-			BigInteger r = generateRandomElement(p, new SecureRandom());
+			BigInteger r = generateRandomElement(p, random);
 			
 			BigInteger u1, u2, v, e, a;
 			
@@ -207,7 +211,7 @@ public class CramerShoupCoreEngine {
 
 		BigInteger result = null;
 
-		if (key.isPrivate() && this.forEncryption && key instanceof CramerShoupPrivateKeyParameters) {
+		if (key.isPrivate() && !this.forEncryption && key instanceof CramerShoupPrivateKeyParameters) {
 			CramerShoupPrivateKeyParameters sk = (CramerShoupPrivateKeyParameters)key;
 			
 			BigInteger p = sk.getParameters().getP();
@@ -251,6 +255,11 @@ public class CramerShoupCoreEngine {
 		return m.compareTo(p) < 0;
 	}
 
+    protected SecureRandom initSecureRandom(boolean needed, SecureRandom provided)
+    {
+        return !needed ? null : (provided != null) ? provided : new SecureRandom();
+    }
+
 	/**
 	 *	CS exception for wrong cipher-texts 
 	 */
diff --git a/core/src/test/java/org/bouncycastle/crypto/test/CramerShoupTest.java b/core/src/test/java/org/bouncycastle/crypto/test/CramerShoupTest.java
index 5b288284..2eb90152 100644
--- a/core/src/test/java/org/bouncycastle/crypto/test/CramerShoupTest.java
+++ b/core/src/test/java/org/bouncycastle/crypto/test/CramerShoupTest.java
@@ -16,7 +16,9 @@ import org.bouncycastle.util.BigIntegers;
 import org.bouncycastle.util.test.SimpleTest;
 
 public class CramerShoupTest extends SimpleTest {
-	
+
+    private static final SecureRandom RND = new SecureRandom();
+
 	private AsymmetricCipherKeyPair keyPair;
 
 	public static void main(String[] args) {
@@ -30,29 +32,18 @@ public class CramerShoupTest extends SimpleTest {
 
 	@Override
 	public void performTest() throws Exception {
+        BigInteger pSubOne = DHStandardGroups.rfc3526_2048.getP().subtract(BigInteger.ONE);
+	    for (int i = 0; i < 10; ++i) {
+            BigInteger message = BigIntegers.createRandomInRange(BigInteger.ONE, pSubOne, RND);
 
-		int i = 0;
-		int numTests = 10;
-		BigInteger message = BigInteger.ONE;
-		
-		while (i < numTests){
-
-			message = BigIntegers.createRandomInRange(BigInteger.ONE,
-					DHStandardGroups.rfc3526_2048.getP().subtract(BigInteger.ONE),
-					new SecureRandom());
-			
 			BigInteger m1 = encDecTest(message);
 			BigInteger m2 = labelledEncDecTest(message, "myRandomLabel");
 			BigInteger m3 = encDecEncodingTest(message);
 			BigInteger m4 = labelledEncDecEncodingTest(message, "myOtherCoolLabel");
-			
-			System.out.println(message);
-			
+
 			if (!message.equals(m1) || !message.equals(m2) || !message.equals(m3) || !message.equals(m4)){
 				fail("decrypted message != original message");
 			}
-		
-			++i;
 		}
 	}
 	
@@ -87,9 +78,9 @@ public class CramerShoupTest extends SimpleTest {
 		
 		CramerShoupCoreEngine engine = new CramerShoupCoreEngine();
 		if (label != null)
-			engine.init(true, keyPair.getPrivate(), label);
+			engine.init(false, keyPair.getPrivate(), label);
 		else
-			engine.init(true, keyPair.getPrivate());
+			engine.init(false, keyPair.getPrivate());
 		try {
 			BigInteger m = engine.decryptBlock(ciphertext);
 			
@@ -109,22 +100,21 @@ public class CramerShoupTest extends SimpleTest {
 		CramerShoupKeyPairGenerator kpGen = new CramerShoupKeyPairGenerator();
 		CramerShoupParametersGenerator pGen = new CramerShoupParametersGenerator();
 		
-		pGen.init(2048, 1, new SecureRandom());
+		pGen.init(2048, 1, RND);
 		CramerShoupParameters params = pGen.generateParameters(DHStandardGroups.rfc3526_2048);
-		CramerShoupKeyGenerationParameters param = new CramerShoupKeyGenerationParameters(new SecureRandom(), params);
+		CramerShoupKeyGenerationParameters param = new CramerShoupKeyGenerationParameters(RND, params);
 
 		kpGen.init(param);
 		keyPair = kpGen.generateKeyPair();
 		
 		CramerShoupCoreEngine engine = new CramerShoupCoreEngine();
 		if (label != null)
-			engine.init(false, keyPair.getPublic(), label);
+			engine.init(true, keyPair.getPublic(), label);
 		else
-			engine.init(false, keyPair.getPublic());
+			engine.init(true, keyPair.getPublic());
 		
 		CramerShoupCiphertext ciphertext = engine.encryptBlock(message);
 		
 		return ciphertext;
 	}
-
 }