unsupported algorithm rsa-sha1

[freddieleeman]

DKIM keeps returning 'invalid' due to 'unsupported algorithm rsa-sha1'. Is there DKIM rsa-sha1 support in the milter or is something else missing?

[freddieleeman]

Never mind, had a closer look at RFC8301 and found:

DKIM supports multiple digital signature algorithms. Two algorithms are defined by this specification at this time: rsa-sha1 and rsa-sha256. Signers MUST sign using rsa-sha256. Verifiers MUST be able to verify using rsa-sha256. rsa-sha1 MUST NOT be used for signing or verifying.

DKIM signatures identified as having been signed with historic algorithms (currently, rsa-sha1) have permanently failed evaluation.