package org.bouncycastle.crypto.engines;import org.bouncycastle.crypto.BlockCipher;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.ParametersWithIV;/** * an implementation of the AES Key Wrapper from the NIST Key Wrap * Specification. * <p> * For further details see: <a href="http://csrc.nist.gov/encryption/kms/key-wrap.pdf">http://csrc.nist.gov/encryption/kms/key-wrap.pdf</a>. */public class AESWrapEngine    implements Wrapper{    private BlockCipher     engine = new AESEngine();    private KeyParameter    param;    private boolean         forWrapping;    private byte[]          iv = {                              (byte)0xa6, (byte)0xa6, (byte)0xa6, (byte)0xa6,                              (byte)0xa6, (byte)0xa6, (byte)0xa6, (byte)0xa6 };    public void init(        boolean             forWrapping,        CipherParameters    param)    {        this.forWrapping = forWrapping;        if (param instanceof KeyParameter)        {            this.param = (KeyParameter)param;        }        else if (param instanceof ParametersWithIV)        {            this.iv = ((ParametersWithIV) param).getIV();            this.param = (KeyParameter) ((ParametersWithIV) param).getParameters();            if (this.iv.length != 8)            {               throw new IllegalArgumentException("IV not multiple of 8");            }        }    }    public String getAlgorithmName()    {        return "AES";    }    public byte[] wrap(        byte[]  in,        int     inOff,        int     inLen)    {        if (!forWrapping)        {            throw new IllegalStateException("not set for wrapping");        }        int     n = inLen / 8;        if ((n * 8) != inLen)        {            throw new DataLengthException("wrap data must be a multiple of 8 bytes");        }        byte[]  block = new byte[inLen + iv.length];        byte[]  buf = new byte[8 + iv.length];        System.arraycopy(iv, 0, block, 0, iv.length);        System.arraycopy(in, 0, block, iv.length, inLen);        engine.init(true, param);        for (int j = 0; j != 6; j++)        {            for (int i = 1; i <= n; i++)            {                System.arraycopy(block, 0, buf, 0, iv.length);                System.arraycopy(block, 8 * i, buf, iv.length, 8);                engine.processBlock(buf, 0, buf, 0);                int t = n * j + i;                for (int k = 1; t != 0; k++)                {                    byte    v = (byte)t;                    buf[iv.length - k] ^= v;                    t >>>= 8;                }                System.arraycopy(buf, 0, block, 0, 8);                System.arraycopy(buf, 8, block, 8 * i, 8);            }        }        return block;    }    public byte[] unwrap(        byte[]  in,        int     inOff,        int     inLen)        throws InvalidCipherTextException    {        if (forWrapping)        {            throw new IllegalStateException("not set for unwrapping");        }        int     n = inLen / 8;        if ((n * 8) != inLen)        {            throw new InvalidCipherTextException("unwrap data must be a multiple of 8 bytes");        }        byte[]  block = new byte[inLen - iv.length];        byte[]  a = new byte[iv.length];        byte[]  buf = new byte[8 + iv.length];        System.arraycopy(in, 0, a, 0, iv.length);        System.arraycopy(in, iv.length, block, 0, inLen - iv.length);        engine.init(false, param);        n = n - 1;        for (int j = 5; j >= 0; j--)        {            for (int i = n; i >= 1; i--)            {                System.arraycopy(a, 0, buf, 0, iv.length);                System.arraycopy(block, 8 * (i - 1), buf, iv.length, 8);                int t = n * j + i;                for (int k = 1; t != 0; k++)                {                    byte    v = (byte)t;                    buf[iv.length - k] ^= v;                    t >>>= 8;                }                engine.processBlock(buf, 0, buf, 0);                System.arraycopy(buf, 0, a, 0, 8);                System.arraycopy(buf, 8, block, 8 * (i - 1), 8);            }        }        for (int i = 0; i != iv.length; i++)        {            if (a[i] != iv[i])            {                throw new InvalidCipherTextException("checksum failed");            }        }        return block;    }}