de.bb.security
Class RC5

java.lang.Object
  |
  +--de.bb.security.BlockCipher
        |
        +--de.bb.security.RC5

public class RC5

extends BlockCipher

RC5-Cipher

based of RFC-2040
tested on vectors found in this RFC (only Blocksize=8)

Fields inherited from class de.bb.security.BlockCipher

blockSize

Constructor Summary

RC5(int _blocksize)
Create a new instance

Method Summary

void	decrypt(byte[] cipherText, int cipherOff, byte[] clearText, int clearOff) Decrypt one Block of "Blocksize"
void	encrypt(byte[] clearText, int clearOff, byte[] cipherText, int cipherOff) Encrypt one Block of "Blocksize"
int	rounds() Getting rounds of inner RC5 transformation.
void	setKey(byte[] keyData) Setting the key for en/decryption.
void	setRounds(int _rounds) Setting rounds of inner RC5 transformation.

Methods inherited from class de.bb.security.BlockCipher

blockSize, decryptCBC, decryptCBCAndPadd, decryptECB, encryptCBC, encryptCBCAndPadd, encryptECB, getBufferLength

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RC5

public RC5(int _blocksize)
    throws java.lang.IllegalArgumentException

Create a new instance

Parameters:

_blocksize - Size of block in bytes to en/decrypt in one step (default 8)

Throws:

java.lang.IllegalArgumentException - Blocksize can be only 4, 8 or 16.

Method Detail

setRounds

public void setRounds(int _rounds)
               throws java.lang.IllegalArgumentException

Setting rounds of inner RC5 transformation.

Parameters:

_rounds - min 0, max 255, default 16 (insecure if rounds < 12)

Throws:

java.lang.IllegalArgumentException - 0 < _rounds < 256

rounds

public int rounds()

Getting rounds of inner RC5 transformation.

setKey

public void setKey(byte[] keyData)
            throws java.lang.IllegalArgumentException

Setting the key for en/decryption.

Overrides:

setKey in class BlockCipher

Parameters:

keyData - the key

Throws:

java.lang.IllegalArgumentException - 0 < keylength < 256

encrypt

public void encrypt(byte[] clearText,
                    int clearOff,
                    byte[] cipherText,
                    int cipherOff)

Encrypt one Block of "Blocksize"

Overrides:

encrypt in class BlockCipher

Following copied from class: de.bb.security.BlockCipher

Parameters:

clearText - input data which is encrypted

clearOff - offset into input data

cipherText - output data which is encrypted.

cipherOff - offset into output data

decrypt

public void decrypt(byte[] cipherText,
                    int cipherOff,
                    byte[] clearText,
                    int clearOff)

Decrypt one Block of "Blocksize"

Overrides:

decrypt in class BlockCipher

Following copied from class: de.bb.security.BlockCipher

Parameters:

cipherText - output data which is encrypted.

cipherOff - offset into output data

clearText - input data which is encrypted

clearOff - offset into input data