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AESWrapEngine.javaAPI DocAndroid 1.5 API4665Wed May 06 22:41:06 BST 2009org.bouncycastle.crypto.engines

AESWrapEngine

public class AESWrapEngine extends Object implements org.bouncycastle.crypto.Wrapper
an implementation of the AES Key Wrapper from the NIST Key Wrap Specification.

For further details see: http://csrc.nist.gov/encryption/kms/key-wrap.pdf.

Fields Summary
private org.bouncycastle.crypto.BlockCipher
engine
private org.bouncycastle.crypto.params.KeyParameter
param
private boolean
forWrapping
private byte[]
iv
Constructors Summary
Methods Summary
public java.lang.StringgetAlgorithmName()

        return "AES";
public voidinit(boolean forWrapping, org.bouncycastle.crypto.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 byte[]unwrap(byte[] in, int inOff, int inLen)

        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;
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;