This is a suggestion for where we can find hash names. Sadly, the existing name "sha1" does not match what other XEPs use ("sha-1"), so we make a special exception for historical reasons. This inconsistency can be fixed up in a future protocol.
Alternatively, we could say that only "sha1" is supported unless support for a new namespace, urn:xmpp:bob#extended or similar is advertised, but this seems like a lot of work on client devs when "just treat this like a special case and define new hash algorithms" probably doesn't require any more work at all if they didn't already support something that was previously unspecified like "sha256".
This is a suggestion for where we can find hash names. Sadly, the existing name "sha1" does not match what other XEPs use ("sha-1"), so we make a special exception for historical reasons. This inconsistency can be fixed up in a future protocol.
Alternatively, we could say that only "sha1" is supported unless support for a new namespace,
urn:xmpp:bob#extendedor similar is advertised, but this seems like a lot of work on client devs when "just treat this like a special case and define new hash algorithms" probably doesn't require any more work at all if they didn't already support something that was previously unspecified like "sha256".