ByteVault-CLI

A high-performance, low-level steganographic tool written in pure C for macOS and Linux. It allows you to securely hide encrypted files or sensitive text payloads inside uncompressed BMP images using the Least Significant Bit (LSB) technique.

Features

• Zero Dependencies: Built using only standard POSIX and C libraries.
• Direct Binary Parsing: Manually parses BITMAPFILEHEADER and BITMAPINFOHEADER byte-by-byte.
• On-the-Fly Encryption: Encrypts data using a custom cascading XOR cipher with a dynamic key prior to injection.
• Anti-Forensic Steganography: Modifies only the lowest bit of each pixel color channel, making the payload completely invisible to the human eye.
• Memory Safe: Strict manual memory management (malloc/free) with zero leaks.

Installation & Compilation

Compile the project with a single command using the provided Makefile:

make

To clean up build artifacts and temporary files:

make clean

Usage

1. Hide a Secret File inside an Image (Encode)

./bytevault -e -i input.bmp -f secret.txt -k YourSecureKey -o hidden.bmp

2. Extract the Hidden File (Decode)

./bytevault -d -i hidden.bmp -k YourSecureKey -o extracted.txt

Technical Overview

The application reads the BMP structure, identifies the pixel data offset via bfOffBits, and embeds 1 bit of the encrypted payload into the youngest bit of each color byte. The first 4 bytes of the embedded stream are reserved for the payload length header, allowing the decoder to stop precisely when all data is recovered.