gnu.crypto.pad
Interface IPad
- BasePad, PKCS1_V1_5, PKCS7, SSL3, TBC, TLS1
The basic visible methods of any padding algorithm.
Padding algorithms serve to
pad and
unpad byte arrays usually
as the last step in an
encryption or respectively a
decryption
operation. Their input buffers are usually those processed by instances of
IMode
and/or
IBlockCipher
.
void | init(int bs) - Initialises the padding scheme with a designated block size.
|
String | name()
|
byte[] | pad(byte[] in, int offset, int length) - Returns the byte sequence that should be appended to the designated input.
|
void | reset() - Resets the scheme instance for re-initialisation and use with other
characteristics.
|
boolean | selfTest() - A basic symmetric pad/unpad test.
|
int | unpad(byte[] in, int offset, int length) - Returns the number of bytes to discard from a designated input buffer.
|
init
public void init(int bs)
throws IllegalStateException
Initialises the padding scheme with a designated block size.
bs
- the designated block size.
name
public String name()
- the canonical name of this instance.
pad
public byte[] pad(byte[] in,
int offset,
int length)
Returns the byte sequence that should be appended to the designated input.
in
- the input buffer containing the bytes to pad.offset
- the starting index of meaningful data in in.length
- the number of meaningful bytes in in.
- the possibly 0-byte long sequence to be appended to the designated
input.
reset
public void reset()
Resets the scheme instance for re-initialisation and use with other
characteristics. This method always succeeds.
selfTest
public boolean selfTest()
A basic symmetric pad/unpad test.
- true if the implementation passes a basic symmetric
self-test. Returns false otherwise.
unpad
public int unpad(byte[] in,
int offset,
int length)
throws WrongPaddingException
Returns the number of bytes to discard from a designated input buffer.
in
- the input buffer containing the bytes to unpad.offset
- the starting index of meaningful data in in.length
- the number of meaningful bytes in in.
- 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.
Copyright © 2001, 2002, 2003
Free Software Foundation,
Inc. All Rights Reserved.