Expand description
§PNG You!
A simple, high-performance library to hide secret messages in a PNG file using steganography.
§How it works
Every PNG file is divided into chunks following specific rules (see PNG Struct Spec). It is, therefore, possible to append our own chunks of data inside a PNG without removing its validity. The crate makes use of this to “hide” data inside a PNG file easily.
§Quick Example
use pngyou::{Png, Chunk, ChunkType};
use std::str::FromStr;
use std::convert::TryFrom;
fn main() -> Result<(), Box<dyn std::error::Error>> {
// Load your PNG file from bytes
let input_bytes = std::fs::read("input.png")?;
let mut png = Png::try_from(input_bytes.as_slice())?;
// Create a custom chunk type and your secret message
let chunk_type = ChunkType::from_str("RuSt")?;
let message = "This is a secret message".as_bytes().to_vec();
// Create the chunk and append it to the PNG
let new_chunk = Chunk::new(chunk_type, message);
png.append_chunk(new_chunk);
// Save the modified PNG back to a file
std::fs::write("output.png", png.as_bytes())?;
Ok(())
}§Features
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PNG Specification Compliance: Strict parsing and validation of PNG structure and chunk types according to the PNG specification.
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Chunk Abstractions: Strongly-typed representations for PNG chunks and chunk types, with semantic validation (critical, public, safe-to-copy).
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Safe Chunk Manipulation: Create, insert, remove, and query chunks without corrupting the PNG file structure.
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CRC Integrity: Automatic computation and verification of CRC values to preserve file correctness.
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Steganography-Friendly: Designed to support custom chunks for data embedding without breaking image decoders.
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Extensible Design: Can be used for general PNG inspection, editing, and tooling beyond steganography use cases.
§CLI Interface
See the pngyou binary for end user usage examples.
