org.logi.crypto.modes
Class EncryptCFB

java.lang.Object
  |
  +--org.logi.crypto.Crypto
        |
        +--org.logi.crypto.modes.EncryptMode
              |
              +--org.logi.crypto.modes.EncryptCFB

public class EncryptCFB
extends EncryptMode

This class implements 8-bit Cipherblock FeedBack mode which encrypts a whole block for each plaintext character. This makes it much slower than ECB or CBC mode, but it can be used for streaming and no garbage is ever inserted.

Author:
Logi Ragnarsson (logir@logi.org)
See Also:
DecryptCFB

Fields inherited from class org.logi.crypto.Crypto
BIT, cdsPath, EMPTY_ARRAY, FOUR, keySource, NIBBLE, ONE, primeCertainty, random, TWO, ZERO
 
Constructor Summary
EncryptCFB()
          Create a new CBF-mode encrypt session with no key.
EncryptCFB(CipherKey key)
          Create a new CBF-mode encrypt session with the specified key.
 
Method Summary
 byte[] encrypt(byte[] source, int i, int length)
          Send bytes to the EncryptCFB object for encryption.
 byte[] flush()
          Pads the internal buffer, encrypts it and returns the ciphertext.
 CipherKey getKey()
          Return the key used for encryption.
 int plainBlockSize()
          Return the size of the blocks of plaintext encrypted by this object.
 void setKey(CipherKey key)
          Set the key to use for encryption.
 
Methods inherited from class org.logi.crypto.modes.EncryptMode
close, finalize, flush
 
Methods inherited from class org.logi.crypto.Crypto
binString, binString, equal, equalRelaxed, equalSub, fromHexNibble, fromHexString, fromString, fromString, hexString, hexString, hexString, hexString, hexString, initRandom, initRandom, makeClass, makeInt, makeLong, makeSessionKey, pastSpace, pickBits, pickBits, readBlock, readInt, writeBytes, writeBytes, writeInt
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

EncryptCFB

public EncryptCFB(CipherKey key)
Create a new CBF-mode encrypt session with the specified key.

EncryptCFB

public EncryptCFB()
Create a new CBF-mode encrypt session with no key. No encryption can be performed until the setKey() method has been called.
Method Detail

getKey

public CipherKey getKey()
Return the key used for encryption.
Overrides:
getKey in class EncryptMode

setKey

public void setKey(CipherKey key)
Set the key to use for encryption. The key can only be set once in this version of the library. The 1.1.x and eventually 1.2.x series allows dynamic re-keying.
Overrides:
setKey in class EncryptMode

plainBlockSize

public int plainBlockSize()
Return the size of the blocks of plaintext encrypted by this object.
Overrides:
plainBlockSize in class EncryptMode

flush

public byte[] flush()
Pads the internal buffer, encrypts it and returns the ciphertext. Since CBF mode doesn't use an internal buffer, an empty array is returned.
Overrides:
flush in class EncryptMode

encrypt

public byte[] encrypt(byte[] source,
                      int i,
                      int length)
Send bytes to the EncryptCFB object for encryption.

Encrypt length bytes from source, starting at i and return the ciphertext.

Overrides:
encrypt in class EncryptMode


Copyright 1997-2000 Logi Ragnarsson