PNGME is a project idea taken from https://jrdngr.github.io/pngme_book/introduction.html.
The code is written in Rust.
There are 4 commands available:
Encodes a secret message into a chunk of specified chunk type, appended to the PNG file given. An output filename can be passed optionally to avoid overwritting the input file.
cargo run -- encode <input.png> --chunk_type <chunk_type_str> --message <some_secret_message> --output <optional_output.png>
Decodes a chunk of specified chunk type from the PNG. If no message is found, it will simply say No message found. Otherwise, it will print out the secret message.
cargo run -- decode <input.png> --chunk_type <chunk_type_str>
Removes a chunk of specified chunk type from the PNG. If no message is found, it will return an error. Otherwise, it will print out the chunk that has been removed.
cargo run -- remove <input.png> --chunk_type <chunk_type_str>
Prints all chunks from the PNG.
cargo run -- print <input.png>
Read more about chunk layout here: http://www.libpng.org/pub/png/spec/1.2/PNG-Structure.html.
The chunk type passed into the commands above must adhere to the specification.