DKIM Crypto Update
|Document||Charter||DKIM Crypto Update WG (dcrup)|
|Title||DKIM Crypto Update|
|IESG||Responsible AD||Alexey Melnikov|
|Charter edit AD||Alexey Melnikov|
|Send notices to||(None)|
The DKIM Crypto Update (DCRUP) Working Group is chartered to update DomainKeys Identified Mail (DKIM, RFC 6376) to handle more modern cryptographic algorithms and key sizes. DKIM (RFC 6376) signatures include a tag that identifies the hash algorithm and signing algorithm used in the signature. The only current algorithm is RSA, with advice that signing keys should be between 1024 and 2048 bits. While 1024 bit signatures are common, longer signatures are not because bugs in DNS provisioning software prevent publishing longer keys as DNS TXT records. DKIM also currently supports use of SHA1 coupled with RSA. SHA1 has been formally deprecated due to weakness in numerous contexts. The community wishes to discourage its continued use in the DKIM context. DCRUP will consider four types of changes to DKIM: additional signing algorithms such as those based on elliptic curves; changes to key strength advice and requirements; deprecating the use of SHA1; and new public key forms, such as putting the public key in the signature and a hash of the key in the DNS to bypass bugs in DNS provisioning software that prevent publishing longer keys as DNS TXT records. Changes will be limited to existing implemented algorithms and key forms. Other changes to DKIM, such as new message canonicalization schemes, are out of scope. The WG will as far as possible avoid changes incompatible with deployed DKIM signers and verifiers.