gosteganography

Simple implementation of the LSB steganography algorithm in go, which uses the least significant bit (LSB) of each colour component (RGB) of each pixel of an image to hide a given message.

It can be used in three ways:

1. As a library: Check the documentation here.
2. As CLI: Read more here.
3. As web app: (using WASM) -> coming soon

What is LSB Steganography?

Steganography is the practice of hiding secret information within an innocuous carrier medium, such as an image or a sound file, in a way that it is undetectable by human senses or analysis tools.

One common method of steganography is to use the least significant bit (LSB) technique, which involves replacing the least significant bit of each pixel in an image or the least significant sample in an audio file with a bit from the secret message. The LSBs are the bits that have the least impact on the overall value of the pixel or sample and therefore changing them slightly will not affect the quality of the media file.

For example, if the value of a pixel is 10101110 in binary, the least significant bit would be 0. If we want to hide a binary message 1101 within the pixel, we can replace the last 4 bits of the pixel with the message bits, resulting in a new pixel value of 10101111.

By repeating this process for all pixels in the image, we can encode the entire secret message. To extract the message, the LSBs of each pixel are simply read and assembled together to reconstruct the original binary message.

However, it is worth noting that LSB steganography is a relatively simple and easily detectable method, and there are more advanced steganography techniques available that offer better security and reliability.

Use & example

Use as CLI tool

1. Installation

   To include gosteganography as CLI run:

    go install github.com/lucasmenendez/gosteganography

2. Run it!

   Lets try:

3. If you need help...

$ > gosteganography help

GoSteganography CLI helps to you to hide a message in a PNG image and unhide it 
from the output.

Usage:

        gosteganography <command> [arguments]

The commands are:

        hide    Hides the content of the secret file in a new copy of input image.
        unhide  Recovers the content of the secret from the input image.

Use in your own code

1. Installation

   To include gosteganography as package dependency run:

    go get github.com/lucasmenendez/gosteganography

2. Import

   To use gosteganography on your application you need to import the following package:

    package main

    import "github.com/lucasmenendez/gosteganography/image"

    func main() {
        // ...
    }

Hide a message

1. Open an image file

    // open the input image
    input, err := os.Open("./input.png")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer input.Close()
    img, err := image.Read(input)
    if err != nil {
        log.Fatal(err)
    }

2. Hide the message into the image

    // hide a message, it returns the number of bits writen
    secret := []byte("secret number: 1234")
    nbits, err := img.Hide(secret)
    if err != nil {
        log.Fatal(err)
    }

3. Write the image with the hidden message into a file

   // store the output
    output, err := os.Create("./output.png")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer output.Close()
    if err := img.Write(output); err != nil {
        log.Fatal(err)
    }

4. Share the image to someone with the number of bits writtem

Unhide the message

1. Open image file

    // open the output image
    output, err := os.Open("./output.png")
    if err != nil {
        fmt.Println(err)
        return
    }
    defer output.Close()
    img, err := image.Read(output)
    if err != nil {
        log.Fatal(err)
    }

2. Unhide the message that the image contains with the number of bits written

    // get hided message using the number of bits
    secret := img.Unhide(nbits)
    fmt.Println(string(secret))

Full example

Input image (original)	Output image (with message hidden)

    package main

    import (
        "fmt"

        "github.com/lucasmenendez/gosteganography/image"
    )

    func main() {
        // open the input image
        input, err := os.Open("./input.png")
        if err != nil {
            fmt.Println(err)
            return
        }
        defer input.Close()
        img, err := image.Read(input)
        if err != nil {
            log.Fatal(err)
        }
        // hide a message, it returns the number of bits writen
        secret := []byte("secret number: 1234")
        nbits, err := img.Hide(secret)
        if err != nil {
            log.Fatal(err)
        }
        // get hided message using the number of bits
        recovered := img.Unhide(nbits)
        fmt.Println(string(recovered))
        // store the output
        output, err := os.Create("./output.png")
        if err != nil {
            fmt.Println(err)
            return
        }
        defer output.Close()
        if err := img.Write(output); err != nil {
            log.Fatal(err)
        }
    }