WbStego
From Just Solve the File Format Problem
wbStego by wbailer is an open source steganography program for Windows and Linux that hides data in BMP, Text/HTML, and PDF files.
Blowfish, Twofish, CAST and Rijndael (AES) encryption is supported in addition to a proprietary Mixing and Encryption algorithm
BMP can be 4, 8 or 24 bit
Text can be ASCII (DOS) or ANSI (Windows) and has 2 modes available:
- Standard method: The file size remains unchanged. When importing manipulated carrier files into word processors (especially under Windows) there can appear special characters in the text.
- Compatible method: The file is being increased. There are no changes visible when a manipulated carrier file is imported into other applications.
PDF has no size limitations, as it embeds hidden objects that PDF readers don't notice.