CFB (GNU cryptographic primitives and tools, version 2.1.0)

Class CFB

public class CFB extends BaseMode

The cipher feedback mode. CFB mode is a stream mode that operates on s bit blocks, where 1 <= s <= b, if b is the underlying cipher's block size. Encryption is:

   I[1] = IV
   I[j] = LSB(b-s, I[j-1]) | C[j-1]   for j = 2...n
   O[j] = CIPH(K, I[j])               for j = 1,2...n
   C[j] = P[j] ^ MSB(s, O[j])         for j = 1,2...n

And decryption is:

   I[1] = IV
   I[j] = LSB(b-s, I[j-1]) | C[j-1]   for j = 2...n
   O[j] = CIPH(K, I[j])               for j = 1,2...n
   P[j] = C[j] ^ MSB(s, O[j])         for j = 1,2...n

CFB mode requires an initialization vector, which need not be kept secret.

References:

Bruce Schneier, Applied Cryptography: Protocols, Algorithms, and Source Code in C, Second Edition. (1996 John Wiley and Sons) ISBN 0-471-11709-9.
Recommendation for Block Cipher Modes of Operation Methods and Techniques, Morris Dworkin.

Version: $Revision: 1.2 $

Constructor Summary
	CFB(IBlockCipher underlyingCipher, int cipherBlockSize) Package-private constructor for the factory class.

Constructor Summary

CFB(IBlockCipher underlyingCipher, int cipherBlockSize)

Package-private constructor for the factory class.

Method Summary
Object	clone()
void	decryptBlock(byte[] in, int inOffset, byte[] out, int outOffset)
void	encryptBlock(byte[] in, int inOffset, byte[] out, int outOffset)
void	setup()
void	teardown()

Method Summary

Object

clone()

void

decryptBlock(byte[] in, int inOffset, byte[] out, int outOffset)

void

encryptBlock(byte[] in, int inOffset, byte[] out, int outOffset)

void

setup()

void

teardown()

Method Detail

public Object clone()

public void decryptBlock(byte[] in, int inOffset, byte[] out, int outOffset)

public void encryptBlock(byte[] in, int inOffset, byte[] out, int outOffset)

public void setup()

public void teardown()