Privacy-Enhanced Electronic Mail
charter-ietf-pem-01

PEM is the outgrowth of work by the Privacy and Security
Research Group (PSRG) of the IRTF. At the heart of PEM is a set of
procedures for transforming RFC 822 messages in such a fashion as to
provide integrity, data origin authenticity, and, optionally,
confidentiality. PEM may be employed with either symmetric or
asymmetric cryptographic key distribution mechanisms. Because the
asymmetric (public-key) mechanisms are better suited to the large
scale, heterogeneously administered environment characteristic of the
Internet, to date only those mechanisms have been standardized. The
standard form adopted by PEM is largely a profile of the CCITT X.509
(Directory Authentication Framework) recommendation.

PEM is defined by a series of documents. The first in the
series defines the message processing procedures. The second defines
the public-key certification system adopted for use with PEM.
The third provides definitions and identifiers for various
algorithms used by PEM. The fourth defines message formats and conventions for
user registration, Certificate Revocation List (CRL) distribution,
etc. (The first three of these were previously issued as RFCs 1113,
1114 and 1115. All documents have been revised and are being issued
first as Internet-Drafts.)