com.ibm.crypto.fips.provider

Interface Padding

public interface Padding

Padding interface. This interface is implemented by general-purpose padding schemes, such as the one described in PKCS#5.

Version:

1.10, 10/26/98

Author:

Jan Luehe, Gigi Ankeny

Method Summary

Methods

Modifier and Type	Method and Description
int	pad(byte[] in, int off, int len) Performs padding for the given data input.
int	padLength(int len) Determines how long the padding will be for a given input length.
void	padWithLen(byte[] in, int off, int len) Adds the given number of padding bytes to the data input.
int	unpad(byte[] in, int off, int len) Returns the index where padding starts.

Method Detail

pad

int pad(byte[] in,
      int off,
      int len)
        throws javax.crypto.ShortBufferException

Performs padding for the given data input. The padding bytes are appended to the data input.

Parameters:

in - the input buffer with the data to pad

off - the offset in in where the data to pad starts

len - the length of the data to pad

Returns:

the number of padding bytes appended

Throws:

javax.crypto.ShortBufferException - if in is too small to hold the padding bytes

padWithLen

void padWithLen(byte[] in,
              int off,
              int len)
                throws javax.crypto.ShortBufferException

Adds the given number of padding bytes to the data input. The value of the padding bytes is determined by the specific padding mechanism that implements this interface.

Parameters:

in - the input buffer with the data to pad

the - offset in in where the padding bytes are appended

len - the number of padding bytes to add

Throws:

javax.crypto.ShortBufferException - if in is too small to hold the padding bytes

unpad

int unpad(byte[] in,
        int off,
        int len)

Returns the index where padding starts.

Given a buffer with data and their padding, this method returns the index where the padding starts.

Parameters:

in - the buffer with the data and their padding

off - the offset in in where the data starts

len - the length of the data and their padding

Returns:

the index where the padding starts, or -1 if the input is not properly padded

padLength

int padLength(int len)

Determines how long the padding will be for a given input length.

Parameters:

len - the length of the data to pad

Returns:

the length of the padding