Command line program that lets you hide secret messages in PNG files.
pngme is a Command Line Interface to modify chunks of PNG files.
I did not come up with the idea for this program but picklenerd did. This is my implementation of the book for learning purposes as a toy project, feel free to use or send pull requests!
To insert a secret message to a PNG file, run: pngme encode file.png chNk "Your message here"
chNk is the type of chunk that your message will be written on. You must use 4 ASCII Alphabetic (a-Z) characters as the type and 3rd byte (character) starting from left should be uppercase. So kaRa, heLo, pnGm are good examples. For more details about chunk types, please visit http://www.libpng.org/pub/png/spec/1.2/PNG-Structure.html
To read a secret message in a PNG file, run: pngme decode file.png chNk
This will print the message in the chNk if there is one.
To find messages, you can use pngme print file.png
This will list all the chunks so be aware. Data of the image is also in chunks and you will not be able to read them because of they are not UTF-8 texts.
To remove message (chunk), you can use pngme remove file.png chNk
You can accidentally delete your image if you would remove image data chunks. Only remove the messages you created! If there is duplication of chunk types, this command will remove the first one.
Run the executable for help as: pngme --help