package org.bouncycastle.crypto.paddings;

import java.security.SecureRandom;

import org.bouncycastle.crypto.InvalidCipherTextException;

A padder that adds the padding according to the scheme referenced in ISO 7814-4 - scheme 2 from ISO 9797-1. The first byte is 0x80, rest is 0x00
/** * A padder that adds the padding according to the scheme referenced in * ISO 7814-4 - scheme 2 from ISO 9797-1. The first byte is 0x80, rest is 0x00 */
public class ISO7816d4Padding implements BlockCipherPadding {
Initialise the padder.
Params:
  • random – - a SecureRandom if available.
/** * Initialise the padder. * * @param random - a SecureRandom if available. */
public void init(SecureRandom random) throws IllegalArgumentException { // nothing to do. }
Return the name of the algorithm the padder implements.
Returns:the name of the algorithm the padder implements.
/** * Return the name of the algorithm the padder implements. * * @return the name of the algorithm the padder implements. */
public String getPaddingName() { return "ISO7816-4"; }
add the pad bytes to the passed in block, returning the number of bytes added.
/** * add the pad bytes to the passed in block, returning the * number of bytes added. */
public int addPadding( byte[] in, int inOff) { int added = (in.length - inOff); in [inOff]= (byte) 0x80; inOff ++; while (inOff < in.length) { in[inOff] = (byte) 0; inOff++; } return added; }
return the number of pad bytes present in the block.
/** * return the number of pad bytes present in the block. */
public int padCount(byte[] in) throws InvalidCipherTextException { int count = in.length - 1; while (count > 0 && in[count] == 0) { count--; } if (in[count] != (byte)0x80) { throw new InvalidCipherTextException("pad block corrupted"); } return in.length - count; } }