SCRAM-SHA-1(-PLUS) + SCRAM-SHA-256(-PLUS) supports

[Neustradamus]

"When using the SASL SCRAM mechanism, the SCRAM-SHA-256-PLUS variant SHOULD be preferred over the SCRAM-SHA-256 variant, and SHA-256 variants [RFC7677] SHOULD be preferred over SHA-1 variants [RFC5802]".

SCRAM-SHA-1(-PLUS):

• https://tools.ietf.org/html/rfc5802
• https://tools.ietf.org/html/rfc6120

SCRAM-SHA-256(-PLUS):

• https://tools.ietf.org/html/rfc7677 since 2015-11-02
• https://tools.ietf.org/html/rfc8600 since 2019-06-21: https://mailarchive.ietf.org/arch/msg/ietf-announce/suJMmeMhuAOmGn_PJYgX5Vm8lNA

SCRAM-SHA-512(-PLUS):

• https://tools.ietf.org/html/draft-melnikov-scram-sha-512

SCRAM-SHA3-512(-PLUS):

• https://tools.ietf.org/html/draft-melnikov-scram-sha3-512

SCRAM BIS: Salted Challenge Response Authentication Mechanism (SCRAM) SASL and GSS-API Mechanisms:

• https://tools.ietf.org/html/draft-melnikov-scram-bis

-PLUS variants:

• RFC5056: On the Use of Channel Bindings to Secure Channels: https://tools.ietf.org/html/rfc5056
• RFC5929: Channel Bindings for TLS: https://tools.ietf.org/html/rfc5929
• Channel-Binding Types: https://www.iana.org/assignments/channel-binding-types/channel-binding-types.xhtml
• Channel Bindings for TLS 1.3: https://datatracker.ietf.org/doc/html/rfc9266

IMAP:

• RFC9051: Internet Message Access Protocol (IMAP) - Version 4rev2: https://tools.ietf.org/html/rfc9051

LDAP:

• RFC5803: Lightweight Directory Access Protocol (LDAP) Schema for Storing Salted: Challenge Response Authentication Mechanism (SCRAM) Secrets: https://tools.ietf.org/html/rfc5803

HTTP:

• RFC7804: Salted Challenge Response HTTP Authentication Mechanism: https://tools.ietf.org/html/rfc7804

JMAP:

• RFC8621: The JSON Meta Application Protocol (JMAP) for Mail: https://tools.ietf.org/html/rfc8621

2FA:

• Extensions to Salted Challenge Response (SCRAM) for 2 factor authentication: https://tools.ietf.org/html/draft-melnikov-scram-2fa

IANA:

• Simple Authentication and Security Layer (SASL) Mechanisms: https://www.iana.org/assignments/sasl-mechanisms/sasl-mechanisms.xhtml

Linked to:

• https://github.com/scram-xmpp/info/issues/1
• https://github.com/RealityRipple/squirrelmail/issues/1
• https://github.com/jult/SquirrelMail/issues/1

[hannob]

I'm not gonna do any functional changes, I'm trying to keep this patchset as small as possible with the stated goals (avoid PHP compatibility issues, warnings and security bugs).

[Neustradamus]

It is about security ;)