Package ch.heigvd.dai.utilities

Class MessageManipulator

java.lang.Object

ch.heigvd.dai.utilities.MessageManipulator

public class MessageManipulator
extends Object

Implements the logic necessary to hide and expose an array of bytes inside a bitmap image, which is itself parsed using the BmpFile class.

Author:

Pedro Alves da Silva, Gonçalo Carvalheiro Heleno

Constructor Summary

Constructors

Constructor	Description
MessageManipulator()

Method Summary

Modifier and Type	Method	Description
void	exposeMessage(BmpFile bmpFile, byte[] message)	Extracts a hidden message from the provided data array.
void	hideMessage(BmpFile bmpFile, byte[] message, int bitsPerByte)	Hides a provided message inside the provided data array.

Methods inherited from class java.lang.Object

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

Constructor Details

MessageManipulator

public MessageManipulator()

Method Details

hideMessage

public void hideMessage(BmpFile bmpFile,
 byte[] message,
 int bitsPerByte)
                 throws MessageManipulationException

Hides a provided message inside the provided data array.

Data array is used as input and output. Each of the (bitsPerByte) LSb of each byte in data are replaced.

Parameters:

bmpFile - the parsed bitmap file from a BmpFile instance

message - the message to hide

bitsPerByte - the number of bits to use per message byte

Throws:

MessageManipulationException - if one of the arguments is not valid

exposeMessage

public void exposeMessage(BmpFile bmpFile,
 byte[] message)
                   throws MessageManipulationException

Extracts a hidden message from the provided data array.

Data array is used as input and output. Each of the (bitsPerByte) LSb of each byte in data are set to 0.

Parameters:

bmpFile - the parsed bitmap file from a BmpFile instance

message - a byte array where the extracted message will be extracted to

Throws:

MessageManipulationException - if one of the arguments is not valid