org.bouncycastle.crypto.paddings.ZeroBytePadding Maven / Gradle / Ivy
package org.bouncycastle.crypto.paddings;
import java.security.SecureRandom;
import org.bouncycastle.crypto.InvalidCipherTextException;
/**
* A padder that adds NULL byte padding to a block.
*/
public class ZeroBytePadding
implements BlockCipherPadding
{
/**
* 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.
*
* @return the name of the algorithm the padder implements.
*/
public String getPaddingName()
{
return "ZeroByte";
}
/**
* 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);
while (inOff < in.length)
{
in[inOff] = (byte) 0;
inOff++;
}
return added;
}
/**
* return the number of pad bytes present in the block.
*/
public int padCount(byte[] in)
throws InvalidCipherTextException
{
int count = in.length;
while (count > 0)
{
if (in[count - 1] != 0)
{
break;
}
count--;
}
return in.length - count;
}
}