gnu.javax.crypto.pad
Class TBC
- IPad
The implementation of the Trailing Bit Complement (TBC) padding algorithm.
In this mode, "...the data string is padded at the trailing end with the
complement of the trailing bit of the unpadded message: if the trailing bit
is
1, then
0 bits are appended, and if the trailing
bit is
0, then
1 bits are appended. As few bits are
added as are necessary to meet the formatting size requirement."
References:
-
Recommendation for Block Cipher Modes of Operation Methods and
Techniques, Morris Dworkin.
byte[] | pad(byte[] in, int offset, int length) - Returns the byte sequence that should be appended to the designated input.
|
void | setup()
|
int | unpad(byte[] in, int offset, int length) - Returns the number of bytes to discard from a designated input buffer.
|
clone , equals , extends Object> getClass , finalize , hashCode , notify , notifyAll , toString , wait , wait , wait |
pad
public byte[] pad(byte[] in,
int offset,
int length)
Returns the byte sequence that should be appended to the designated input.
- pad in interface IPad
- pad in interface BasePad
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.
unpad
public int unpad(byte[] in,
int offset,
int length)
throws WrongPaddingException
Returns the number of bytes to discard from a designated input buffer.
- unpad in interface IPad
- unpad in interface BasePad
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
.
TBC.java --
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