📦 pkieltyka / stash

================================================================ ____ / || | | | \ \| / ` / __| '_ \ ) | || (| \ \ | | | |/ \\,|/| || VERSION: 0.3

Copyright (C) 2003 Peter Kieltyka Jan 27, 2003 Updated: Mar 25, 2006 ================================================================

Contents:

[1] What is Stash? [2] Usage information [3] License [4] Misc

-- [1] What is Stash? ------------------------------------------

Stash is a basic steganography program that hides a file within a bitmap image without disrupting the appearance of the original image. It uses a simple algorithm that replaces the least significant bit of a random set of bytes from the pixel data of the bitmap image with a bit of the secret data. The bits are distributed throughout the container file (BMP) as determined by the password supplied to seed the PRNG.

-- [2] Usage information ---------------------------------------

Usage Examples: To Hide: ./stash "image1.bmp" "image2.bmp" "secret.txt" "hello123" To Extract: ./stash "image2.bmp" "secret.txt" "hello123"

Tested on:

• Windows XP

• FreeBSD 4.7

• Debian Linux 3.0

• Mac OS X 10.3

• Implement AES cipher to encrypt the data before hiding it

• Add JPEG/WAV/MPG support

-- [3] License -------------------------------------------------

Stash is licensed under the BSD license. See the attached LICENSE file.

-- [4] Misc ----------------------------------------------------

code notes: ===========

when hiding: a = (a & ~1) | (((b >> (7-k)) & 1) & 1);

this takes the bit of byte 'b' at location 'k' (k goes from 0-7, 0 being the LSB) and stores it in the LSB of byte 'a'

when extracting: a = (a & ~(1 << (7-k))) | ((b & 1) << (7-k));

this assigns 'a' the LSB of 'b' to location 'k' (k goes from 0-7, 0 being the LSB)