The project aim to be used for educational purposes. The following tool hide a message into a PNG image. The producer of the message can hidde the message using WriteSecretMessage.py. The receptor of the image can read the hidden message using the ReadSecretMessage.py.

You can hidde a secret message using the least significant bits. The technique is called Steganography and can be applied to both grayscale and color images. In color images, channels like Red, Green, and Blue (RGB) can be used independently or jointly to hide information. This technique used in the code involve modify the values of the first color channels to encode the hidden data.

Given a input image in PNG format like this example:

Encoding a message

from WriteSecretMessage import WriteSecretMessage
from ReadSecretMessage import ReadSecretMessage

end_of_message_token = [1, 1, 1, 1, 1, 1, 1, 1] # dec 255 => ÿ
secret_message = "Greeting from Germany!"
m = WriteSecretMessage(secret_message, "Igel.png","Igel2.png", end_of_message_token)
m.hidde_message_in_picture()

The code produces the output image (Igel2.png) which is apparently the same as the original image (Igel.png). This technique make the changes indetectable to the human eyes.

The image produced with the hidden message is the following:

Decoding the message

concat = ''.join(map(str, end_of_message_token))
p = ReadSecretMessage("Igel2.png", concat )
print(f">>> Hidden message: {p.decode_message()}")

The end of message token is used to indicate the end of message and also is used to detect and finish the decoding process.

Run the code

$ python3 main.py
>>> WriteSecretMessage! 'Greeting from Germany!' in picture: Igel.png
Image size: (4032, 3024)
Message len: 184
The message has been written correctly!
>>> Decoding message of picture: Igel2.png
>>> Hidden message: Greeting from Germany!

Have fun !