Domain Keys Identified Mail
charter-ietf-dkim-04

Internet mail protocols do not certify the validity of any
identification information associated with a message, including
the author's name and address. This limits the ability to
determine legitimate accountability for a message. It also limits
the ability to determine unauthorized uses of these identifiers.

The DKIM working group has produced two standards-track
specifications. The first allows a domain to take responsibility,
using digital signatures, for having taken part in the
transmission of an email message. The second allows a domain to
publish information about its practices in applying those
signatures. Taken together, these allow receiving domains to
ascertain responsibility for a message, and possibly to detect
some unauthorized assertions of authorship.

While the techniques specified by the DKIM working group will not
prevent fraud or spam, they can assist in efforts to establish a
basis for identifying actors that can be trusted. The
standards-track specifications do not mandate any particular
action by the receiving domain when a signature fails to validate.
That said, with the understanding that guidance is necessary for
implementers, the DKIM documents discuss a reasonable set of
possible actions and strategies, and analyze their likely effects
on attacks and on normal email delivery.

+++ Previous Work +++
The previously chartered deliverables for the DKIM working group
have been completed. To provide background, we list them here:

• An informational RFC presenting a detailed threat analysis of,
  and security requirements for, DKIM. (RFC 4686)

• A standards-track specification for DKIM signature and
  verification. (RFC 4871, updated by RFC 5672)

• A standards-track specification for DKIM policy handling.
  (RFC 5617)

• An informational RFC providing an overview of DKIM and how it
  can fit into overall messaging systems, how it relates to other
  IETF message signature technologies, implementation and
  migration considerations, and outlining potential DKIM
  applications and future extensions. (RFC 5585 and
  draft-ietf-dkim-deployment, in its final stages)

(One previously chartered deliverable, a standards-track
specification for DKIM DNS Resource Record(s), was dropped by
agreement between the working group and the Area Directors.)

+++ New Work +++
The working group is now ready to switch its focus to refining and
advancing the DKIM protocols. The current deliverables for the
DKIM working group are these:

1. Advance the base DKIM protocol (RFC 4871) to Draft Standard.
   This is the first priority for the working group.

2. Collect data on the deployment, interoperability, and
   effectiveness of the base DKIM protocol, with consideration
   toward updating the working group's informational documents.

3. Collect data on the deployment, interoperability, and
   effectiveness of the Author Domain Signing Practices protocol
   (RFC 5617), and determine if/when it's ready to advance on the
   standards track. Update it at Proposed Standard, advance it to
   Draft Standard, deprecate it, or determine another disposition,
   as appropriate.

4. Taking into account the data collected in (2) and (3), update
   the overview and deployment/operations documents. These are
   considered living documents, and should be updated periodically,
   as we have more real-world experience.

5. Consider issues related to mailing lists, beyond what is
   already documented. This includes considerations for mailing
   list software that supports or intends to support DKIM, as well
   as considerations for DKIM/ADSP deployment in the presence of
   mailing lists that do not have such support. Include
   recommendations in the informational documents, or produce a
   new informational document about mailing-list considerations.

+++ What's Out Of Scope +++
As before, several related topics remain out of scope for the DKIM
working group. These topics include:

• Reputation and accreditation systems. While we expect these to
  add value to what is defined by the DKIM working group, their
  development will be separate, and is out of scope for the DKIM
  working group.

• Message content encryption.

• Additional key management protocols or infrastructure.

• Signatures that are intended to make long-term assertions beyond
  the expected transit time of a message from originator to
  recipient, which is normally only a matter of a few days at
  most.

• Signatures that attempt to make strong assertions about the
  identity of the message author, and details of user-level
  signing of messages (as distinguished from domain-level keys
  that are restricted to specific users).

• Duplication of prior work in signed email, including S/MIME and
  OpenPGP.