Examples with DataLengthException org.gudy.bouncycastle.crypto.DataLengthException used on opensource projects

Example 1 with DataLengthException

use of org.gudy.bouncycastle.crypto.DataLengthException in project BiglyBT by BiglySoftware.

the class RSAEngine method processBlock.

/**
 * Process a single block using the basic RSA algorithm.
 *
 * @param in the input array.
 * @param inOff the offset into the input buffer where the data starts.
 * @param inLen the length of the data to be processed.
 * @return the result of the RSA process.
 * @exception DataLengthException the input block is too large.
 */
@Override
public byte[] processBlock(byte[] in, int inOff, int inLen) {
    if (inLen > (getInputBlockSize() + 1)) {
        throw new DataLengthException("input too large for RSA cipher.\n");
    } else if (inLen == (getInputBlockSize() + 1) && (in[inOff] & 0x80) != 0) {
        throw new DataLengthException("input too large for RSA cipher.\n");
    }
    byte[] block;
    if (inOff != 0 || inLen != in.length) {
        block = new byte[inLen];
        System.arraycopy(in, inOff, block, 0, inLen);
    } else {
        block = in;
    }
    BigInteger input = new BigInteger(1, block);
    byte[] output;
    if (key instanceof RSAPrivateCrtKeyParameters) {
        // 
        // we have the extra factors, use the Chinese Remainder Theorem - the author
        // wishes to express his thanks to Dirk Bonekaemper at rtsffm.com for
        // advice regarding the expression of this.
        // 
        RSAPrivateCrtKeyParameters crtKey = (RSAPrivateCrtKeyParameters) key;
        BigInteger p = crtKey.getP();
        BigInteger q = crtKey.getQ();
        BigInteger dP = crtKey.getDP();
        BigInteger dQ = crtKey.getDQ();
        BigInteger qInv = crtKey.getQInv();
        BigInteger mP, mQ, h, m;
        // mP = ((input mod p) ^ dP)) mod p
        mP = (input.remainder(p)).modPow(dP, p);
        // mQ = ((input mod q) ^ dQ)) mod q
        mQ = (input.remainder(q)).modPow(dQ, q);
        // h = qInv * (mP - mQ) mod p
        h = mP.subtract(mQ);
        h = h.multiply(qInv);
        // mod (in Java) returns the positive residual
        h = h.mod(p);
        // m = h * q + mQ
        m = h.multiply(q);
        m = m.add(mQ);
        output = m.toByteArray();
    } else {
        output = input.modPow(key.getExponent(), key.getModulus()).toByteArray();
    }
    if (forEncryption) {
        if (// have ended up with an extra zero byte, copy down.
        output[0] == 0 && output.length > getOutputBlockSize()) {
            byte[] tmp = new byte[output.length - 1];
            System.arraycopy(output, 1, tmp, 0, tmp.length);
            return tmp;
        }
        if (// have ended up with less bytes than normal, lengthen
        output.length < getOutputBlockSize()) {
            byte[] tmp = new byte[getOutputBlockSize()];
            System.arraycopy(output, 0, tmp, tmp.length - output.length, output.length);
            return tmp;
        }
    } else {
        if (// have ended up with an extra zero byte, copy down.
        output[0] == 0) {
            byte[] tmp = new byte[output.length - 1];
            System.arraycopy(output, 1, tmp, 0, tmp.length);
            return tmp;
        }
    }
    return output;
}

Example 2 with DataLengthException

use of org.gudy.bouncycastle.crypto.DataLengthException in project BiglyBT by BiglySoftware.

the class CTSBlockCipher method doFinal.

/**
 * Process the last block in the buffer.
 *
 * @param out the array the block currently being held is copied into.
 * @param outOff the offset at which the copying starts.
 * @return the number of output bytes copied to out.
 * @exception DataLengthException if there is insufficient space in out for
 * the output.
 * @exception IllegalStateException if the underlying cipher is not
 * initialised.
 * @exception InvalidCipherTextException if cipher text decrypts wrongly (in
 * case the exception will never get thrown).
 */
@Override
public int doFinal(byte[] out, int outOff) throws DataLengthException, IllegalStateException, InvalidCipherTextException {
    if (bufOff + outOff > out.length) {
        throw new DataLengthException("output buffer to small in doFinal");
    }
    int blockSize = cipher.getBlockSize();
    int len = bufOff - blockSize;
    byte[] block = new byte[blockSize];
    if (forEncryption) {
        cipher.processBlock(buf, 0, block, 0);
        for (int i = bufOff; i != buf.length; i++) {
            buf[i] = block[i - blockSize];
        }
        for (int i = blockSize; i != bufOff; i++) {
            buf[i] ^= block[i - blockSize];
        }
        if (cipher instanceof CBCBlockCipher) {
            BlockCipher c = ((CBCBlockCipher) cipher).getUnderlyingCipher();
            c.processBlock(buf, blockSize, out, outOff);
        } else {
            cipher.processBlock(buf, blockSize, out, outOff);
        }
        System.arraycopy(block, 0, out, outOff + blockSize, len);
    } else {
        byte[] lastBlock = new byte[blockSize];
        if (cipher instanceof CBCBlockCipher) {
            BlockCipher c = ((CBCBlockCipher) cipher).getUnderlyingCipher();
            c.processBlock(buf, 0, block, 0);
        } else {
            cipher.processBlock(buf, 0, block, 0);
        }
        for (int i = blockSize; i != bufOff; i++) {
            lastBlock[i - blockSize] = (byte) (block[i - blockSize] ^ buf[i]);
        }
        System.arraycopy(buf, blockSize, block, 0, len);
        cipher.processBlock(block, 0, out, outOff);
        System.arraycopy(lastBlock, 0, out, outOff + blockSize, len);
    }
    int offset = bufOff;
    reset();
    return offset;
}