StreamCipher.java revision e6bf3e8dfa2804891a82075cb469b736321b4827 
1package org.bouncycastle.crypto;
2
3/**
4 * the interface stream ciphers conform to.
5 */
6public interface StreamCipher
7{
8    /**
9     * Initialise the cipher.
10     *
11     * @param forEncryption if true the cipher is initialised for
12     *  encryption, if false for decryption.
13     * @param params the key and other data required by the cipher.
14     * @exception IllegalArgumentException if the params argument is
15     * inappropriate.
16     */
17    public void init(boolean forEncryption, CipherParameters params)
18        throws IllegalArgumentException;
19
20    /**
21     * Return the name of the algorithm the cipher implements.
22     *
23     * @return the name of the algorithm the cipher implements.
24     */
25    public String getAlgorithmName();
26
27    /**
28     * encrypt/decrypt a single byte returning the result.
29     *
30     * @param in the byte to be processed.
31     * @return the result of processing the input byte.
32     */
33    public byte returnByte(byte in);
34
35    /**
36     * process a block of bytes from in putting the result into out.
37     *
38     * @param in the input byte array.
39     * @param inOff the offset into the in array where the data to be processed starts.
40     * @param len the number of bytes to be processed.
41     * @param out the output buffer the processed bytes go into.
42     * @param outOff the offset into the output byte array the processed data starts at.
43     * @exception DataLengthException if the output buffer is too small.
44     */
45    public void processBytes(byte[] in, int inOff, int len, byte[] out, int outOff)
46        throws DataLengthException;
47
48    /**
49     * reset the cipher. This leaves it in the same state
50     * it was at after the last init (if there was one).
51     */
52    public void reset();
53}
54