Several standard and tools use the value of the authentication scheme, so it would be helpful to have a standardized value for the HTTP scheme. For example, the OpenAPI specification specifies the "scheme" attribute: https://swagger.io/specification/#securitySchemeObject
Shouldn't "Signature" (or equivalent string) be added as a valid authentication scheme to the IANA Authentication Scheme Registry, which is located at https://www.iana.org/assignments/http-authschemes/http-authschemes.xhtml?
Version 12 of the HTTP-signature draft references RFC 7235 section 4.1, but I don't see any reference to RFC 7235 section 5.1. https://tools.ietf.org/html/rfc7235#section-5.1
Several standard and tools use the value of the authentication scheme, so it would be helpful to have a standardized value for the HTTP scheme. For example, the OpenAPI specification specifies the "scheme" attribute: https://swagger.io/specification/#securitySchemeObject