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org.bouncycastle.crypto.engines.DSTU7624WrapEngine Maven / Gradle / Ivy
package org.bouncycastle.crypto.engines;
import java.util.ArrayList;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.Wrapper;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.util.Arrays;
/**
* Implementation of DSTU7624 KEY WRAP mode
*/
public class DSTU7624WrapEngine
implements Wrapper
{
private static final int BYTES_IN_INTEGER = 4;
private boolean forWrapping;
private DSTU7624Engine engine;
private byte[] B, intArray;
private byte[] checkSumArray, zeroArray;
private ArrayList Btemp;
public DSTU7624WrapEngine(int blockBitLength)
{
this.engine = new DSTU7624Engine(blockBitLength);
this.B = new byte[engine.getBlockSize() / 2];
this.checkSumArray = new byte[engine.getBlockSize()];
this.zeroArray = new byte[engine.getBlockSize()];
this.Btemp = new ArrayList();
this.intArray = new byte[BYTES_IN_INTEGER];
}
public void init(boolean forWrapping, CipherParameters param)
{
if (param instanceof ParametersWithRandom)
{
param = ((ParametersWithRandom)param).getParameters();
}
this.forWrapping = forWrapping;
if (param instanceof KeyParameter)
{
engine.init(forWrapping, param);
}
else
{
throw new IllegalArgumentException("invalid parameters passed to DSTU7624WrapEngine");
}
}
public String getAlgorithmName()
{
return "DSTU7624WrapEngine";
}
public byte[] wrap(byte[] in, int inOff, int inLen)
{
if (!forWrapping)
{
throw new IllegalStateException("not set for wrapping");
}
if ((inLen % engine.getBlockSize()) != 0)
{
//Partial blocks not supported
throw new DataLengthException("wrap data must be a multiple of " + engine.getBlockSize() + " bytes");
}
if (inOff + inLen > in.length)
{
throw new DataLengthException("input buffer too short");
}
int n = 2 * (1 + inLen / engine.getBlockSize()); /* Defined in DSTU7624 standard */
int V = (n - 1) * 6; /* Defined in DSTU7624 standard */
byte[] wrappedBuffer = new byte[inLen + engine.getBlockSize()];
System.arraycopy(in, inOff, wrappedBuffer, 0, inLen);
System.arraycopy(wrappedBuffer, 0, B, 0, engine.getBlockSize() / 2);
Btemp.clear();
int bHalfBlocksLen = wrappedBuffer.length - engine.getBlockSize() / 2;
int bufOff = engine.getBlockSize() / 2;
while (bHalfBlocksLen != 0)
{
byte[] temp = new byte[engine.getBlockSize() / 2];
System.arraycopy(wrappedBuffer, bufOff, temp, 0, engine.getBlockSize() / 2);
Btemp.add(temp);
bHalfBlocksLen -= engine.getBlockSize() / 2;
bufOff += engine.getBlockSize() / 2;
}
for (int j = 0; j < V; j++)
{
System.arraycopy(B, 0, wrappedBuffer, 0, engine.getBlockSize() / 2);
System.arraycopy(Btemp.get(0), 0, wrappedBuffer, engine.getBlockSize() / 2, engine.getBlockSize() / 2);
engine.processBlock(wrappedBuffer, 0, wrappedBuffer, 0);
intToBytes(j + 1, intArray, 0);
for (int byteNum = 0; byteNum < BYTES_IN_INTEGER; byteNum++)
{
wrappedBuffer[byteNum + engine.getBlockSize() / 2] ^= intArray[byteNum];
}
System.arraycopy(wrappedBuffer, engine.getBlockSize() / 2, B, 0, engine.getBlockSize() / 2);
for (int i = 2; i < n; i++)
{
System.arraycopy(Btemp.get(i - 1), 0, Btemp.get(i - 2), 0, engine.getBlockSize() / 2);
}
System.arraycopy(wrappedBuffer, 0, Btemp.get(n - 2), 0, engine.getBlockSize() / 2);
}
System.arraycopy(B, 0, wrappedBuffer, 0, engine.getBlockSize() / 2);
bufOff = engine.getBlockSize() / 2;
for (int i = 0; i < n - 1; i++)
{
System.arraycopy(Btemp.get(i), 0, wrappedBuffer, bufOff, engine.getBlockSize() / 2);
bufOff += engine.getBlockSize() / 2;
}
return wrappedBuffer;
}
public byte[] unwrap(byte[] in, int inOff, int inLen)
throws InvalidCipherTextException
{
if (forWrapping)
{
throw new IllegalStateException("not set for unwrapping");
}
if ((inLen % engine.getBlockSize()) != 0)
{
//Partial blocks not supported
throw new DataLengthException("unwrap data must be a multiple of " + engine.getBlockSize() + " bytes");
}
int n = 2 * inLen / engine.getBlockSize();
int V = (n - 1) * 6;
byte[] buffer = new byte[inLen];
System.arraycopy(in, inOff, buffer, 0, inLen);
byte[] B = new byte[engine.getBlockSize() / 2];
System.arraycopy(buffer, 0, B, 0, engine.getBlockSize() / 2);
Btemp.clear();
int bHalfBlocksLen = buffer.length - engine.getBlockSize() / 2;
int bufOff = engine.getBlockSize() / 2;
while (bHalfBlocksLen != 0)
{
byte[] temp = new byte[engine.getBlockSize() / 2];
System.arraycopy(buffer, bufOff, temp, 0, engine.getBlockSize() / 2);
Btemp.add(temp);
bHalfBlocksLen -= engine.getBlockSize() / 2;
bufOff += engine.getBlockSize() / 2;
}
for (int j = 0; j < V; j++)
{
System.arraycopy(Btemp.get(n - 2), 0, buffer, 0, engine.getBlockSize() / 2);
System.arraycopy(B, 0, buffer, engine.getBlockSize() / 2, engine.getBlockSize() / 2);
intToBytes(V - j, intArray, 0);
for (int byteNum = 0; byteNum < BYTES_IN_INTEGER; byteNum++)
{
buffer[byteNum + engine.getBlockSize() / 2] ^= intArray[byteNum];
}
engine.processBlock(buffer, 0, buffer, 0);
System.arraycopy(buffer, 0, B, 0, engine.getBlockSize() / 2);
for (int i = 2; i < n; i++)
{
System.arraycopy(Btemp.get(n - i - 1), 0, Btemp.get(n - i), 0, engine.getBlockSize() / 2);
}
System.arraycopy(buffer, engine.getBlockSize() / 2, Btemp.get(0), 0, engine.getBlockSize() / 2);
}
System.arraycopy(B, 0, buffer, 0, engine.getBlockSize() / 2);
bufOff = engine.getBlockSize() / 2;
for (int i = 0; i < n - 1; i++)
{
System.arraycopy(Btemp.get(i), 0, buffer, bufOff, engine.getBlockSize() / 2);
bufOff += engine.getBlockSize() / 2;
}
System.arraycopy(buffer, buffer.length - engine.getBlockSize(), checkSumArray, 0, engine.getBlockSize());
byte[] wrappedBuffer = new byte[buffer.length - engine.getBlockSize()];
if (!Arrays.areEqual(checkSumArray, zeroArray))
{
throw new InvalidCipherTextException("checksum failed");
}
else
{
System.arraycopy(buffer, 0, wrappedBuffer, 0, buffer.length - engine.getBlockSize());
}
return wrappedBuffer;
}
private void intToBytes(int number, byte[] outBytes, int outOff)
{
outBytes[outOff + 3] = (byte)(number >> 24);
outBytes[outOff + 2] = (byte)(number >> 16);
outBytes[outOff + 1] = (byte)(number >> 8);
outBytes[outOff] = (byte)number;
}
}
