gnu.crypto.pad

Class SSL3

Implemented Interfaces:
IPad

public class SSL3
extends BasePad

The padding scheme used by the Secure Sockets Layer, version 3. This padding scheme is used in the block-ciphered struct, e.g.:
 block-ciphered struct {
   opaque content[SSLCompressed.length];
   opaque MAC[CipherSpec.hash_size];
   uint8 padding[GenericBlockCipher.padding_length];
   uint8 padding_length;
 } GenericBlockCipher;
 

Where padding_length is cipher_block_size - ((SSLCompressed.length + CipherSpec.hash_size) % cipher_block_size) - 1. That is, the padding is enough bytes to make the plaintext a multiple of the block size minus one, plus one additional byte for the padding length. The padding can be any arbitrary data.

Field Summary

Fields inherited from class gnu.crypto.pad.BasePad

blockSize, name

Constructor Summary

SSL3()

Method Summary

byte[]
pad(byte[] in, int off, int len)
Returns the byte sequence that should be appended to the designated input.
void
setup()
int
unpad(byte[] in, int off, int len)
Returns the number of bytes to discard from a designated input buffer.

Methods inherited from class gnu.crypto.pad.BasePad

init, name, pad, reset, selfTest, setup, unpad

Constructor Details

SSL3

public SSL3()

Method Details

pad

public byte[] pad(byte[] in,
                  int off,
                  int len)
Returns the byte sequence that should be appended to the designated input.
Specified by:
pad in interface IPad
Overrides:
pad in interface BasePad
Parameters:
in - the input buffer containing the bytes to pad.
Returns:
the possibly 0-byte long sequence to be appended to the designated input.

setup

public void setup()
Overrides:
setup in interface BasePad

unpad

public int unpad(byte[] in,
                 int off,
                 int len)
            throws WrongPaddingException
Returns the number of bytes to discard from a designated input buffer.
Specified by:
unpad in interface IPad
Overrides:
unpad in interface BasePad
Parameters:
in - the input buffer containing the bytes to unpad.
Returns:
the number of bytes to discard, to the left of index position offset + length in in. In other words, if the return value of a successful invocation of this method is result, then the unpadded byte sequence will be offset + length - result bytes in in, starting from index position offset.
Throws:
WrongPaddingException - if the data is not terminated with the expected padding bytes.

Copyright © 2001, 2002, 2003 Free Software Foundation, Inc. All Rights Reserved.