iaik.cms

Class MacInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

iaik.cms.MacInputStream

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class MacInputStream
extends java.io.FilterInputStream

This class is a stream supporting Message Authentication Code (MAC). It calculates a MAC value based on the stream of bytes contained in the given InputStream. The MAC calculated depends on the javax.crypto.Mac algorithm that was passed to it.

Since:

8.1

Field Summary

Fields

Modifier and Type	Field and Description
protected javax.crypto.Mac	mac

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
MacInputStream(java.io.InputStream stream, javax.crypto.Mac mac) The Constructor for the MacInputStream.

Method Summary

Modifier and Type	Method and Description
javax.crypto.Mac	getMac()
int	read() Reads a single byte from the Stream and updates the Mac calculation based on the byte read.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes and updates the Mac calculation based on the bytes read.

Methods inherited from class java.io.FilterInputStream

available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

mac

protected javax.crypto.Mac mac

Constructor Detail

MacInputStream

public MacInputStream(java.io.InputStream stream,
                      javax.crypto.Mac mac)

The Constructor for the MacInputStream.

Parameters:

stream - the InputStream to be wrapped

mac - The Mac algorithm to use

Method Detail

read

public int read()
         throws java.io.IOException

Reads a single byte from the Stream and updates the Mac calculation based on the byte read.

Overrides:

read in class java.io.FilterInputStream

Throws:

java.io.IOException

read

public int read(byte[] b,
                int off,
                int len)
         throws java.io.IOException

Reads up to len bytes of data from the input stream into an array of bytes and updates the Mac calculation based on the bytes read.

An attempt is made to read as many as len bytes, but a smaller number may be read. The number of bytes actually read is returned as an integer. This method blocks until input data is available, end of file is detected, or an exception is thrown.

Parameters:

Overrides:

read in class java.io.FilterInputStream

Parameters:

b - the buffer into which the data is read.

off - the start offset in array b at which the data is written.

len - the maximum number of bytes to read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

java.io.IOException

getMac

public javax.crypto.Mac getMac()

Returns:

The Mac value