Example usage for org.bouncycastle.crypto.paddings BlockCipherPadding addPadding

Introduction

In this page you can find the example usage for org.bouncycastle.crypto.paddings BlockCipherPadding addPadding.

Prototype

public int addPadding(byte[] in, int inOff);

Source Link

Document

add the pad bytes to the passed in block, returning the number of bytes added.

Usage

From source file:snodes.net.Packet.java

License:Open Source License

/**
 * Encrypts the packet using the given key.
 *
 * @param bytes//from  w ww  .j  a v a2 s .com
 *     The packet data.
 * @param key
 *     The packet key.
 * @return
 *     The encrypted packet data.
 * @throws IllegalArgumentException
 *     If <tt>key</tt> is too short.
 */
private static byte[] encrypt(byte[] bytes, Key key) throws IllegalArgumentException {
    logger.fine("Encrypting packet with key " + key);

    KeyParameter fishkey = new KeyParameter(key.toByteArray());
    TwofishEngine twofish = new TwofishEngine();
    int blocksize = twofish.getBlockSize();
    int blocks = (int) Math.ceil((double) bytes.length / (double) blocksize);

    twofish.init(true, fishkey); // true = encrypt
    byte[] encrypted = new byte[blocks * blocksize]; // Leave room for padding

    for (int i = 0; i < blocks; i++) {
        byte[] block = new byte[blocksize];
        int offset = i * blocksize;
        int written = 0;

        // Pad if not enough bytes -- otherwise, exception is thrown
        if (bytes.length - offset < blocksize) {
            BlockCipherPadding pad = new PKCS7Padding();
            int padLen = bytes.length - offset;
            byte[] write = new byte[blocksize];
            int padding = 0;

            System.arraycopy(bytes, offset, write, 0, padLen);

            pad.init(new SecureRandom());
            padding = pad.addPadding(write, padLen);

            written = twofish.processBlock(write, 0, block, 0);
        } else {
            written = twofish.processBlock(bytes, offset, block, 0);
        }

        System.arraycopy(block, 0, encrypted, offset, written);
    }

    return encrypted;
}

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