Technical Summary
The document specifies describes an augmented password-authenticated key
exchange (PAKE) protocol OPAQUE. It supports mutual authentication in a
client-server setting without reliance on certificates and with security
against offline/pre-computation attacks upon server compromise. This document
is a product of the Crypto Forum Research Group (CFRG) in the IRTF.
Research Group Summary
The OPAQUE protocol was selected as a result of the PAKE selection process in
CFRG in 2019; there were a lot of reviews of the protocol and the early
versions of the draft (https://github.com/cfrg/pake-selection). The document
was adopted in September 2020. There was a Research Group Last Call for the
draft in 2024 (January-June). A number of concerns raised during the RGLC were
addressed by the authors. The authors have answered the questions raised during
the Research Group Last Call. Crypto Review Panel review was solicited in 2024
(January-April). The reviews were provided by Chloe Martindale, Jean-Philippe
Aumasson, Julia Hesse, Scott Fluhrer. Comments from that review were addressed
in -14, -15, and -16.
Document Quality
There are several publicly available implementations: reference, Sage
(https://github.com/cfrg/draft-irtf-cfrg-opaque/tree/master/poc), Rust
(https://github.com/novifinancial/opaque-ke), Go
(https://github.com/bytemare/opaque/), C (https://github.com/stef/libopaque,
https://github.com/aldenml/ecc) TypeScript
(https://github.com/cloudflare/opaque-ts).
All authors of the document have confirmed that they are not aware of any IPRs
related to the document.
Personnel
Stanislav Smyshlyaev is the Document Shepherd.
Colin Perkins is the IRTF Chair.