org.logi.crypto.modes
Class DecryptCFB

java.lang.Object
  |
  +--org.logi.crypto.Crypto
        |
        +--org.logi.crypto.modes.DecryptMode
              |
              +--org.logi.crypto.modes.DecryptCFB
All Implemented Interfaces:
DecryptSession

public class DecryptCFB
extends org.logi.crypto.modes.DecryptMode

Use this class to decrypt ciphertext generated by EncryptCFB.

Note that unlike ECB or CBC mode, CFB mode uses the same key to encrypt and decrypt, even with asymmetric ciphers.

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

Fields inherited from class org.logi.crypto.Crypto
BIT, cdsPath, EMPTY_ARRAY, FOUR, keySource, NIBBLE, ONE, primeCertainty, random, TWO, ZERO
 
Constructor Summary
DecryptCFB()
          Create a new CFB-mode decrypt session with no key.
DecryptCFB(DecryptionKey key)
          Create a new CFB-mode decrypt session with the specified key.
 
Method Summary
 byte[] decrypt(byte[] source, int i, int length)
          Send bytes to the DecryptCFB object for encryption.
 byte[] flush()
          Flush any buffers internal to the DecryptSession object and releases any and all resources.
 byte[] flush(byte[] source, int i, int length)
          Decrypt the last part of ciphertext and return plaintext.
 DecryptionKey getKey()
          Return the key used for decryption.
 int plainBlockSize()
          Return the size of the blocks of plaintext output by this object.
 void setKey(DecryptionKey key)
          Set the key to use for decryption.
 
Methods inherited from class org.logi.crypto.Crypto
binString, binString, ensureArrayLength, ensureArrayLength, equal, equalRelaxed, equalSub, fromHexNibble, fromHexString, fromString, fromString, hexString, hexString, hexString, hexString, hexString, initRandom, initRandom, makeClass, makeInt, makeLong, makeSessionKey, pastSpace, pickBits, pickBits, prettyPrint, prettyPrint, readBlock, readInt, trimArrayLength, trimArrayLength, trimLeadingZeroes, writeBytes, writeBytes, writeInt
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DecryptCFB

public DecryptCFB(DecryptionKey key)
           throws KeyException
Create a new CFB-mode decrypt session with the specified key.
Throws:
KeyException - if key is a public key.

DecryptCFB

public DecryptCFB()
Create a new CFB-mode decrypt session with no key. No decryption can be performed until a call to setKey() has been made.
Method Detail

getKey

public DecryptionKey getKey()
Return the key used for decryption.

setKey

public void setKey(DecryptionKey key)
            throws KeyException
Set the key to use for decryption.
Throws:
KeyException - if key is a public key.

plainBlockSize

public int plainBlockSize()
Return the size of the blocks of plaintext output by this object.

decrypt

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

Decrypt length bytes from source, starting at i and return the plaintext.


flush

public byte[] flush()
Description copied from interface: DecryptSession
Flush any buffers internal to the DecryptSession object and releases any and all resources.

flush

public byte[] flush(byte[] source,
                    int i,
                    int length)
             throws CryptoException
Decrypt the last part of ciphertext and return plaintext. This will flush any buffers internal to the DecryptSession object.
Specified by:
flush in interface DecryptSession


Copyright (c) 1997-2001 Logi Ragnarsson - Distributed under the GPL