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Fix the bug if block size of base in GCFBBlockCipher is not equal to 8.
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gefeili committed Jan 2, 2025
1 parent 2c9faf6 commit e6fc301
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Showing 3 changed files with 81 additions and 25 deletions.
50 changes: 26 additions & 24 deletions core/src/main/java/org/bouncycastle/crypto/modes/GCFBBlockCipher.java
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,8 @@ public class GCFBBlockCipher
private ParametersWithIV initParams;

private KeyParameter key;
private long counter = 0;
private boolean forEncryption;
private long counter = 0;
private boolean forEncryption;

public GCFBBlockCipher(BlockCipher engine)
{
Expand All @@ -43,13 +43,13 @@ public void init(boolean forEncryption, CipherParameters params)
{
counter = 0;
cfbEngine.init(forEncryption, params);
byte[] iv = null;
byte[] iv = null;

this.forEncryption = forEncryption;

if (params instanceof ParametersWithIV)
{
ParametersWithIV ivParams = (ParametersWithIV) params;
ParametersWithIV ivParams = (ParametersWithIV)params;
params = ivParams.getParameters();
iv = ivParams.getIV();
}
Expand All @@ -65,14 +65,14 @@ public void init(boolean forEncryption, CipherParameters params)
}

key = (KeyParameter)params;
/* Pick up key/IV from parameters or most recent parameters */
if (key == null && initParams != null)
{
key = (KeyParameter) initParams.getParameters();

/* Pick up key/IV from parameters or most recent parameters */
if (key == null && initParams != null)
{
key = (KeyParameter)initParams.getParameters();
}
if (iv == null && initParams != null)
{
{
iv = initParams.getIV();
}
else
Expand Down Expand Up @@ -105,18 +105,20 @@ public int processBlock(byte[] in, int inOff, byte[] out, int outOff)

protected byte calculateByte(byte b)
{
if (counter > 0 && counter % 1024 == 0)
if (counter > 0 && (counter & 1023) == 0)
{
BlockCipher base = cfbEngine.getUnderlyingCipher();
BlockCipher base = cfbEngine.getUnderlyingCipher();

base.init(false, key);

byte[] nextKey = new byte[32];

base.processBlock(C, 0, nextKey, 0);
base.processBlock(C, 8, nextKey, 8);
base.processBlock(C, 16, nextKey, 16);
base.processBlock(C, 24, nextKey, 24);
int blockSize = base.getBlockSize();
//TODO: The for-loop will not function correctly if 32 is not evenly divisible by blocksize
// (i.e., 32 % blocksize != 0), So it's not working for DSTU7624Engine(512), RijndaelEngine(except 256), etc.
for (int i = 0; i < nextKey.length; i += blockSize)
{
base.processBlock(C, i, nextKey, i);
}

key = new KeyParameter(nextKey);

Expand All @@ -137,13 +139,13 @@ protected byte calculateByte(byte b)
public void reset()
{
counter = 0;
if (initParams != null)
{
key = (KeyParameter) initParams.getParameters();
if (initParams != null)
{
key = (KeyParameter)initParams.getParameters();
cfbEngine.init(forEncryption, initParams);
}
else
{
}
else
{
cfbEngine.reset();
}
}
Expand Down
51 changes: 51 additions & 0 deletions core/src/test/java/org/bouncycastle/crypto/test/CipherTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -3,8 +3,10 @@
import java.security.SecureRandom;

import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.CipherKeyGenerator;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.DefaultBufferedBlockCipher;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.KeyGenerationParameters;
import org.bouncycastle.crypto.modes.AEADCipher;
Expand All @@ -14,6 +16,7 @@
import org.bouncycastle.util.test.SimpleTest;
import org.bouncycastle.util.test.SimpleTestResult;
import org.bouncycastle.util.test.TestFailedException;
import org.junit.Assert;

public abstract class CipherTest
extends SimpleTest
Expand Down Expand Up @@ -251,4 +254,52 @@ static void isEqualTo(
throw new TestFailedException(SimpleTestResult.failed(parent, "no message"));
}
}

static void checkCipher(final BlockCipher pCipher, final int datalen)
throws Exception
{
final SecureRandom random = new SecureRandom();
/* Create the data */
final byte[] myData = new byte[datalen];
random.nextBytes(myData);

/* Create the Key parameters */
final CipherKeyGenerator myGenerator = new CipherKeyGenerator();
final KeyGenerationParameters myGenParams = new KeyGenerationParameters(random, 256);
myGenerator.init(myGenParams);
final byte[] myKey = myGenerator.generateKey();
final KeyParameter myKeyParams = new KeyParameter(myKey);

/* Create the IV */
final byte[] myIV = new byte[16];
random.nextBytes(myIV);

/* Create the initParams */
final ParametersWithIV myParams = new ParametersWithIV(myKeyParams, myIV);

/* Wrap Block Cipher with buffered BlockCipher */
final BufferedBlockCipher myCipher = new DefaultBufferedBlockCipher(pCipher);

/* Initialise the cipher for encryption */
myCipher.init(true, myParams);

/* Encipher the text */
final byte[] myOutput = new byte[myCipher.getOutputSize(datalen)];
int myOutLen = myCipher.processBytes(myData, 0, datalen, myOutput, 0);
myCipher.doFinal(myOutput, myOutLen);

/* Re-Encipher the text (after implicit reset) */
final byte[] myOutput2 = new byte[myCipher.getOutputSize(datalen)];
myOutLen = myCipher.processBytes(myData, 0, datalen, myOutput2, 0);
myCipher.doFinal(myOutput2, myOutLen);

myCipher.init(false, myParams);
final byte[] plaintext = new byte[myCipher.getOutputSize(myOutput.length)];
myOutLen = myCipher.processBytes(myOutput2, 0, datalen, plaintext, 0);
myCipher.doFinal(plaintext, myOutLen);

/* Check that the cipherTexts are identical */
Assert.assertArrayEquals(myOutput, myOutput2);
Assert.assertArrayEquals(myData, plaintext);
}
}
5 changes: 4 additions & 1 deletion core/src/test/java/org/bouncycastle/crypto/test/GOST28147Test.java
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Original file line number Diff line number Diff line change
Expand Up @@ -4,9 +4,11 @@
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.CryptoException;
import org.bouncycastle.crypto.digests.GOST3411Digest;
import org.bouncycastle.crypto.engines.AESEngine;
import org.bouncycastle.crypto.engines.GOST28147Engine;
import org.bouncycastle.crypto.modes.CBCBlockCipher;
import org.bouncycastle.crypto.modes.CFBBlockCipher;
import org.bouncycastle.crypto.modes.GCFBBlockCipher;
import org.bouncycastle.crypto.modes.GOFBBlockCipher;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;
Expand Down Expand Up @@ -197,7 +199,8 @@ public void performTest()
throws Exception
{
super.performTest();

checkCipher(new GCFBBlockCipher(new GOST28147Engine()), 2049);
checkCipher(new GCFBBlockCipher(AESEngine.newInstance()), 2049);
//advanced tests with GOST28147KeyGenerator:
//encrypt on hesh message; ECB mode:
byte[] in = Hex.decode("4e6f77206973207468652074696d6520666f7220616c6c20");
Expand Down

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