#chacha20-poly1305 #stream #wrapper #encryption #decryption


A writable wrapper stream for encryption and decryption with the stream cipher chacha20_poly1305

9 stable releases

2.2.1 Aug 20, 2021
2.1.0 Aug 16, 2021
2.0.1 Aug 14, 2021
1.0.3 May 8, 2021
1.0.2 Apr 8, 2021

#543 in Cryptography

41 downloads per month

MIT license

1.5K SLoC

chacha20_poly1305 stream wrapper

Contains a writable stream that wraps another, applying the chacha20_poly1305 cipher to the input before writing for either encryption or decryption.

Usage example

Encrypt and decrypt message with an in-memory buffer.

// Generate random key and IV for the operations.
let (key, iv) = chacha20stream::keygen();

let input = "Hello world!";

// Encryption into a new `Vec<u8>`. (Any implementor of `io::Write` or `&mut io::Write` can be used.)
let mut sink = Sink::encrypt(Vec::new(), key, iv).expect("Failed to create encryptor");
sink.flush().unwrap(); // `flush` also clears the in-memory buffer if there is left over data in it.

let output_encrypted = sink.into_inner();

// Decryption into a new `Vec<u8>`. (Any implementor of `std::io::Write` or `&mut std::io::Write` can be used.)
let mut sink = Sink::decrypt(Vec::new(), key, iv).expect("Failed to create decryptor");

let output_decrypted = sink.into_inner();

assert_eq!(&output_decrypted[..], input.as_bytes());


  • smallvec - Use smallvec crate to store the in-memory buffer on the stack if it's smalle enough (default)
  • async - Enable AsyncSink with Tokio 0.2 AsyncWrite. The API is the same as for the regular Sink.
  • explicit_clear - Explicitly clear in-memory buffer after operations.
  • ffi - Build with the C FFI interface (see include/cc20.h.) The output libraries are generated in target/{debug,release}/libchacha20stream.{a,so}.




~66K SLoC