org.bouncycastle.crypto.paddings

Interface BlockCipherPadding

Known Implementing Classes:
ISO10126d2Padding, ISO7816d4Padding, PKCS7Padding, TBCPadding, X923Padding, ZeroBytePadding

public interface BlockCipherPadding

Block cipher padders are expected to conform to this interface

Method Summary

int
addPadding(byte[] in, int inOff)
add the pad bytes to the passed in block, returning the number of bytes added.
String
getPaddingName()
Return the name of the algorithm the cipher implements.
void
init(SecureRandom random)
Initialise the padder.
int
padCount(byte[] in)
return the number of pad bytes present in the block.

Method Details

addPadding

public int addPadding(byte[] in,
                      int inOff)
add the pad bytes to the passed in block, returning the number of bytes added.

Note: this assumes that the last block of plain text is always passed to it inside in. i.e. if inOff is zero, indicating the entire block is to be overwritten with padding the value of in should be the same as the last block of plain text. The reason for this is that some modes such as "trailing bit compliment" base the padding on the last byte of plain text.


getPaddingName

public String getPaddingName()
Return the name of the algorithm the cipher implements.
Returns:
the name of the algorithm the cipher implements.

init

public void init(SecureRandom random)
            throws IllegalArgumentException
Initialise the padder.
Parameters:
random - the source of randomness for the padding, if required.

padCount

public int padCount(byte[] in)
            throws InvalidCipherTextException
return the number of pad bytes present in the block.
Throws:
InvalidCipherTextException - if the padding is badly formed or invalid.