import org.spongycastle.util.Pack; //导入依赖的package包/类
/**
 * fill len bytes of the output buffer with bytes generated from the
 * derivation function.
 * 
 * @throws IllegalArgumentException
 *             if the size of the request will cause an overflow.
 * @throws DataLengthException
 *             if the out buffer is too small.
 */
public int generateBytes(byte[] out, int outOff, int len) throws DataLengthException,
        IllegalArgumentException
{
    if ((out.length - len) < outOff)
    {
        throw new DataLengthException("output buffer too small");
    }

    long oBytes = len;
    int outLen = digest.getDigestSize();

    //
    // this is at odds with the standard implementation, the
    // maximum value should be hBits * (2^32 - 1) where hBits
    // is the digest output size in bits. We can't have an
    // array with a long index at the moment...
    //
    if (oBytes > ((2L << 32) - 1))
    {
        throw new IllegalArgumentException("Output length too large");
    }

    int cThreshold = (int)((oBytes + outLen - 1) / outLen);

    byte[] dig = new byte[digest.getDigestSize()];

    byte[] C = new byte[4];
    Pack.intToBigEndian(counterStart, C, 0);

    int counterBase = counterStart & ~0xFF;

    for (int i = 0; i < cThreshold; i++)
    {
        digest.update(C, 0, C.length);
        digest.update(shared, 0, shared.length);

        if (iv != null)
        {
            digest.update(iv, 0, iv.length);
        }

        digest.doFinal(dig, 0);

        if (len > outLen)
        {
            System.arraycopy(dig, 0, out, outOff, outLen);
            outOff += outLen;
            len -= outLen;
        }
        else
        {
            System.arraycopy(dig, 0, out, outOff, len);
        }

        if (++C[3] == 0)
        {
            counterBase += 0x100;
            Pack.intToBigEndian(counterBase, C, 0);
        }
    }

    digest.reset();

    return (int)oBytes;
}
 

import org.spongycastle.util.Pack; //导入依赖的package包/类
/**
 * fill len bytes of the output buffer with bytes generated from the
 * derivation function.
 * 
 * @throws IllegalArgumentException
 *             if the size of the request will cause an overflow.
 * @throws DataLengthException
 *             if the out buffer is too small.
 */
public int generateBytes(byte[] out, int outOff, int len) throws DataLengthException,
        IllegalArgumentException
{
    if ((out.length - len) < outOff)
    {
        throw new DataLengthException("output buffer too small");
    }

    long oBytes = len;
    int outLen = digest.getDigestSize();

    //
    // this is at odds with the standard implementation, the
    // maximum value should be hBits * (2^32 - 1) where hBits
    // is the digest output size in bits. We can't have an
    // array with a long index at the moment...
    //
    if (oBytes > ((2L << 32) - 1))
    {
        throw new IllegalArgumentException("Output length too large");
    }

    int cThreshold = (int)((oBytes + outLen - 1) / outLen);

    byte[] dig = new byte[digest.getDigestSize()];

    byte[] c = new byte[4];
    Pack.intToBigEndian(counterStart, c, 0);

    int counterBase = counterStart & ~0xFF;

    for (int i = 0; i < cThreshold; i++)
    {
        digest.update(c, 0, c.length);
        digest.update(shared, 0, shared.length);

        if (iv != null)
        {
            digest.update(iv, 0, iv.length);
        }

        digest.doFinal(dig, 0);

        if (len > outLen)
        {
            System.arraycopy(dig, 0, out, outOff, outLen);
            outOff += outLen;
            len -= outLen;
        }
        else
        {
            System.arraycopy(dig, 0, out, outOff, len);
        }

        if (++c[3] == 0)
        {
            counterBase += 0x100;
            Pack.intToBigEndian(counterBase, c, 0);
        }
    }

    digest.reset();

    return (int)oBytes;
}
 

import org.spongycastle.util.Pack; //导入依赖的package包/类
private static void updateRecordMACLength(Mac mac, int len) {
    byte[] longLen = Pack.longToLittleEndian(len & 0xFFFFFFFFL);
    mac.update(longLen, 0, longLen.length);
}
 

import org.spongycastle.util.Pack; //导入依赖的package包/类
private byte[] encryptBlock(byte[] in, int inOff, int inLen) throws InvalidCipherTextException {
    byte[] C = null, K = null, K1 = null, K2 = null;
    int len;

    if (cipher == null) {
        // Streaming mode.
        K1 = new byte[inLen];
        K2 = new byte[param.getMacKeySize() / 8];
        K = new byte[K1.length + K2.length];

        kdf.generateBytes(K, 0, K.length);

        if (V.length != 0) {
            System.arraycopy(K, 0, K2, 0, K2.length);
            System.arraycopy(K, K2.length, K1, 0, K1.length);
        } else {
            System.arraycopy(K, 0, K1, 0, K1.length);
            System.arraycopy(K, inLen, K2, 0, K2.length);
        }

        C = new byte[inLen];

        for (int i = 0; i != inLen; i++) {
            C[i] = (byte) (in[inOff + i] ^ K1[i]);
        }
        len = inLen;
    } else {
        // Block cipher mode.
        K1 = new byte[((IESWithCipherParameters) param).getCipherKeySize() / 8];
        K2 = new byte[param.getMacKeySize() / 8];
        K = new byte[K1.length + K2.length];

        kdf.generateBytes(K, 0, K.length);
        System.arraycopy(K, 0, K1, 0, K1.length);
        System.arraycopy(K, K1.length, K2, 0, K2.length);

        // If iv provided use it to initialise the cipher
        if (IV != null) {
            cipher.init(true, new ParametersWithIV(new KeyParameter(K1), IV));
        } else {
            cipher.init(true, new KeyParameter(K1));
        }

        C = new byte[cipher.getOutputSize(inLen)];
        len = cipher.processBytes(in, inOff, inLen, C, 0);
        len += cipher.doFinal(C, len);
    }

    // Convert the length of the encoding vector into a byte array.
    byte[] P2 = param.getEncodingV();
    byte[] L2 = new byte[4];
    if (V.length != 0 && P2 != null) {
        Pack.intToBigEndian(P2.length * 8, L2, 0);
    }

    // Apply the MAC.
    byte[] T = new byte[mac.getMacSize()];

    byte[] K2a = new byte[hash.getDigestSize()];
    hash.reset();
    hash.update(K2, 0, K2.length);
    hash.doFinal(K2a, 0);
    mac.init(new KeyParameter(K2a));
    mac.update(IV, 0, IV.length);
    mac.update(C, 0, C.length);
    if (P2 != null) {
        mac.update(P2, 0, P2.length);
    }
    if (V.length != 0) {
        mac.update(L2, 0, L2.length);
    }
    mac.doFinal(T, 0);

    // Output the triple (V,C,T).
    byte[] Output = new byte[V.length + len + T.length];
    System.arraycopy(V, 0, Output, 0, V.length);
    System.arraycopy(C, 0, Output, V.length, len);
    System.arraycopy(T, 0, Output, V.length + len, T.length);
    return Output;
}