RFC: https://datatracker.ietf.org/doc/html/rfc9421

Draft RFC: https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-mes...

Related:

Curl native support for –aws-sigv4 (2023) - https://news.ycombinator.com/item?id=40888314 - July 2024 (17 comments)

HTTP Message Signatures - https://news.ycombinator.com/item?id=40249765 - May 2024 (3 comments)