http://www.rfc-editor.org/rfc/rfc7539.txt
RFC 7539: ChaCha20 and Poly1305 for IETF Protocols, Y. Nir, A. Langley2015-05-01T23:00:00-00:00This document does not introduce any new crypto, but is meant to serve as a stable reference and an implementation guide. It is a product of the Crypto Forum Research Group (CFRG).