iaik.utils

Class MacInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

iaik.utils.MacInputStream

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

public class MacInputStream
extends java.io.FilterInputStream

A stream implementation for MACing the data read from an input stream. This is similar to the java.security.DigestInputStream.

Version:

File Revision 3

See Also:

MacOutputStream, DigestInputStream

Field Summary

Fields

Modifier and Type	Field and Description
protected javax.crypto.Mac	macEngine_ The MAC engine to use for MACing the data.
protected boolean	macingActive_ Indicates, if this objects sends data read from this stream to the Mac engine.

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
MacInputStream(java.io.InputStream stream, javax.crypto.Mac macEngine) Creates a MAC input stream, using the specified input stream and MAC engine.

Method Summary

Methods

Modifier and Type	Method and Description
javax.crypto.Mac	getMac() Get the MAC engine used for MACing the data.
void	on(boolean macingActive) Turns the MACing on or off.
int	read() This methods reads a byte fom the underlying stream and upadtes the MAC with this data, if the MACing is active.
int	read(byte[] dataByteArray, int offset, int length) This methods reads data bytes fom the underlying stream and upadtes the MAC with this data, if the MACing is active.
void	setMac(javax.crypto.Mac macEngine) Set the MAC engine to use for MACing the data.
java.lang.String	toString() Returns a string representation of this MAC output stream.

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, wait, wait, wait

Field Detail

macingActive_

protected boolean macingActive_

Indicates, if this objects sends data read from this stream to the Mac engine.

macEngine_

protected javax.crypto.Mac macEngine_

The MAC engine to use for MACing the data.

Constructor Detail

MacInputStream

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

Creates a MAC input stream, using the specified input stream and MAC engine.

Parameters:

stream - The input stream to read the data from.

macEngine - The MAC engine to use for MACing the data.

Method Detail

getMac

public javax.crypto.Mac getMac()

Get the MAC engine used for MACing the data.

Returns:

The MAC engine used for MACing the data.

setMac

public void setMac(javax.crypto.Mac macEngine)

Set the MAC engine to use for MACing the data.

Parameters:

macEngine - The MAC engine to use for MACing the data.

read

public int read()
         throws java.io.IOException

This methods reads a byte fom the underlying stream and upadtes the MAC with this data, if the MACing is active.

Overrides:

read in class java.io.FilterInputStream

Returns:

The data byte read from the underlying stream, or -1, if end of file is reached.

Throws:

java.io.IOException - If reading from the underlaying stream fails.

read

public int read(byte[] dataByteArray,
       int offset,
       int length)
         throws java.io.IOException

This methods reads data bytes fom the underlying stream and upadtes the MAC with this data, if the MACing is active.

Overrides:

read in class java.io.FilterInputStream

Parameters:

dataByteArray - The array receiving the new data bytes.

offset - The offset in the data byte array to start writing the data bytes.

length - The maximum number of bytes to read the stream.

Returns:

The actual number of bytes read from the stream or -1, if end of file was reached before reading the first byte.

Throws:

java.io.IOException - If reading from the underlaying stream fails.

on

public void on(boolean macingActive)

Turns the MACing on or off. If set to false, all data is just written through to the underlying stream but not to the MAC. Otherwise, if set to true, this object writes all data to the MAC as well as to the underlying stream.

Parameters:

macingActive - True, to MAC all data before writing to the underlying stream.

toString

public java.lang.String toString()

Returns a string representation of this MAC output stream.

Overrides:

toString in class java.lang.Object

Returns:

A string representation of this MAC output stream.