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gnu.crypto.pad
Class SSL3

java.lang.Object
  extended by gnu.crypto.pad.BasePad
      extended by gnu.crypto.pad.SSL3
All 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()
          If any additional checks or resource setup must be done by the subclass, then this is the hook for it.
 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, reset, selfTest
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SSL3

public SSL3()
Method Detail

setup

public void setup()
Description copied from class: BasePad

If any additional checks or resource setup must be done by the subclass, then this is the hook for it. This method will be called before the BasePad.init(int) method returns.

Specified by:
setup in class BasePad

pad

public byte[] pad(byte[] in,
                  int off,
                  int len)
Description copied from interface: IPad
Returns the byte sequence that should be appended to the designated input.

Specified by:
pad in interface IPad
Specified by:
pad in class BasePad
Parameters:
in - the input buffer containing the bytes to pad.
off - the starting index of meaningful data in in.
len - the number of meaningful bytes in in.
Returns:
the possibly 0-byte long sequence to be appended to the designated input.

unpad

public int unpad(byte[] in,
                 int off,
                 int len)
          throws WrongPaddingException
Description copied from interface: IPad
Returns the number of bytes to discard from a designated input buffer.

Specified by:
unpad in interface IPad
Specified by:
unpad in class BasePad
Parameters:
in - the input buffer containing the bytes to unpad.
off - the starting index of meaningful data in in.
len - the number of meaningful bytes in in.
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.

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