com.ibm.crypto.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.


Method Summary
 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 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:
ShortBufferException - if in is too small to hold the padding bytes

padWithLen

void padWithLen(byte[] in,
                int off,
                int len)
                throws 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:
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