cryptix.provider.padding
public class PKCS5 extends PaddingScheme
...
An IllegalBlockSizeException is thrown (by the Cipher class) if the block size is not 8 bytes.
References:
Copyright © 1997
Systemics Ltd on behalf of the
Cryptix Development Team.
All rights reserved.
$Revision: 1.7 $
Since: Cryptix 2.2.2
Constructor Summary | |
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PKCS5() Creates a PKCS5 object. |
Method Summary | |
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protected boolean | engineIsValidBlockSize(int size)
SPI: Returns true if size is a valid block size (in
bytes) for this algorithm.
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protected int | enginePad(byte[] in, int offset, int length)
Pads a given array of bytes. |
protected int | engineUnpad(byte[] in, int offset, int length)
Given the specified subarray of bytes that includes padding bytes, returns
the index indicating where padding starts.
|
For PKCS#5 padding, the only valid size is 8 bytes.
in[offset+length..offset+7]
.
Parameters: in the buffer containing the incomplete block. offset the offset into the in
buffer of the
first byte in the group of bytes to be padded. length the number of bytes from the in
buffer,
starting at offset
, that need to be padded.
For PKCS#5, the padding bytes all have value
8 - (length % 8)
. Hence to find the number
of added bytes, it's enough to consider the last byte value of the
padded message.
Parameters: in the buffer containing the bytes. offset the offset into the in buffer of the first byte in the block. length the length of the block in bytes.
Returns: the index into the in buffer indicating where the padding starts.
Throws: CryptixException if the number of padding bytes is invalid.