[dispatch] Proposed charter for DCRUP v0.2

["John R Levine" <[e-mail]>]

A few minor changes per recent suggestions: modify -> update, allow
deprecation of 512 bit RSA keys, don't be incompatible.

R's,
John

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The DKIM Crypto Update (DCRUP) working groupkin is chartered to update
DKIM 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.

DCRUP will consider three types of changes to DKIM: additional signing
algorithms such as those based on elliptic curves, changes to key
strength advice and requirements, and new public key forms, such as
putting the public key in the signature and a hash of the key in the
DNS.  It will limit itself 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.