The IESG has approved the following two Internet-Drafts as Proposed
Standards:
1. MIME Object Security Services <draft-ietf-pem-mime-08.txt>
2. Security Multiparts for MIME: Multipart/Signed and
Multipart/Encrypted
<draft-ietf-pem-sigenc-03.txt>
These documents are the product of the Privacy-Enhanced Electronic Mail
Working Group. The IESG contact person is Jeffrey Schiller.
Technical Summary
These documents describe a general framework for security within MIME
(draft-ietf-pem-sigenc-03.txt) and a specific proposal for offering
Privacy Enhanced Mail services within MIME(draft-ietf-pem-mime-08.txt).
Support is provided for digital signatures on MIME objects (both simple
and compound) as well as for confidentiality provided through data
encryption.
A key design goal is to provide a MIME parseable structure for signed
MIME objects (without requiring that signature verification occur prior
to complete parsing). Another important goal is to provide for "one
pass" processing of signed and/or encrypted MIME objects.
Working Group Summary
After extensive discussion and debate the PEM working group has come to
a rough consensus on these documents. One difference still outstanding
has to do with key/certificate hierarchies and how they are
structured. One camp is in favor of a flexible approach that permits
implementors, site administrators and end-users to determine the key
trust mechanism appropriate for their environment. The other camp
insists that only X.509 certificates, issued by well defined
certification authorities, should be supported. This is to ensure the
ability to provide security services which scale to the whole
Internet.
The documents proposed for standardization here attempt to strike a
balance by providing for both X.509 certification as well as other
approaches that may be defined in the future. As written they can form
a basis for two different mail security services (represented by the
strict hierarchy approach on one side and the flexible mechanism
approach on the other) which share a common MIME interchange format.
Ultimately two mail efforts may be required because the requirements,
goals and potential user community for the two approaches are very
different.
Protocol Quality
Jeff Schiller reviewed these protocols for the IESG. The need for
security services on the Internet and the protection of sensitive
information exchanged via messaging systems in particular is acute.
These proposals provide a good solution for adding signatures and
encryption to MIME services in an environment where we desire the over
all structure to remain parseable where signature verification services
may not always be available.