org.bouncycastle.crypto.engines

Class ElGamalEngine

Implemented Interfaces:
AsymmetricBlockCipher

public class ElGamalEngine
extends java.lang.Object
implements AsymmetricBlockCipher

this does your basic ElGamal algorithm.

Method Summary

int
getInputBlockSize()
Return the maximum size for an input block to this engine.
int
getOutputBlockSize()
Return the maximum size for an output block to this engine.
void
init(boolean forEncryption, CipherParameters param)
initialise the ElGamal engine.
byte[]
processBlock(byte[] in, int inOff, int inLen)
Process a single block using the basic ElGamal algorithm.

Method Details

getInputBlockSize

public int getInputBlockSize()
Return the maximum size for an input block to this engine. For ElGamal this is always one byte less than the size of P on encryption, and twice the length as the size of P on decryption.
Specified by:
getInputBlockSize in interface AsymmetricBlockCipher
Returns:
maximum size for an input block.

getOutputBlockSize

public int getOutputBlockSize()
Return the maximum size for an output block to this engine. For ElGamal this is always one byte less than the size of P on decryption, and twice the length as the size of P on encryption.
Specified by:
getOutputBlockSize in interface AsymmetricBlockCipher
Returns:
maximum size for an output block.

init

public void init(boolean forEncryption,
                 CipherParameters param)
initialise the ElGamal engine.
Specified by:
init in interface AsymmetricBlockCipher
Parameters:
forEncryption - true if we are encrypting, false otherwise.
param - the necessary ElGamal key parameters.

processBlock

public byte[] processBlock(byte[] in,
                           int inOff,
                           int inLen)
Process a single block using the basic ElGamal algorithm.
Specified by:
processBlock in interface AsymmetricBlockCipher
Parameters:
in - the input array.
inOff - the offset into the input buffer where the data starts.
inLen - the length of the data to be processed.
Returns:
the result of the ElGamal process.