package org.bouncycastle.crypto;
/**
* the interface stream ciphers conform to.
*/
public interface StreamCipher
{
/**
* Initialise the cipher.
*
* @param forEncryption if true the cipher is initialised for
* encryption, if false for decryption.
* @param params the key and other data required by the cipher.
* @exception IllegalArgumentException if the params argument is
* inappropriate.
*/
public void init(boolean forEncryption, CipherParameters params)
throws IllegalArgumentException;
/**
* Return the name of the algorithm the cipher implements.
*
* @return the name of the algorithm the cipher implements.
*/
public String getAlgorithmName();
/**
* encrypt/decrypt a single byte returning the result.
*
* @param in the byte to be processed.
* @return the result of processing the input byte.
*/
public byte returnByte(byte in);
/**
* process a block of bytes from in putting the result into out.
*
* @param in the input byte array.
* @param inOff the offset into the in array where the data to be processed starts.
* @param len the number of bytes to be processed.
* @param out the output buffer the processed bytes go into.
* @param outOff the offset into the output byte array the processed data starts at.
* @return the number of bytes produced - should always be len.
* @exception DataLengthException if the output buffer is too small.
*/
public int processBytes(byte[] in, int inOff, int len, byte[] out, int outOff)
throws DataLengthException;
/**
* reset the cipher. This leaves it in the same state
* it was at after the last init (if there was one).
*/
public void reset();
}