Privacy Enhancement for Internet Electronic Mail: Part I: Message Encryption and Authentication Procedures (RFC1421)
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2000-Sep-12
Internet Society Requests For Comment (RFCs)
Status of this Memo
Network Working Group J. Linn
Request for Comments: 1421 IAB IRTF PSRG, IETF PEM WG
Obsoletes: 1113 February 1993
Privacy Enhancement for Internet Electronic Mail:
Part I: Message Encryption and Authentication Procedures
Status of this Memo
This RFC specifies an IAB standards track protocol for the Internet
community, and requests discussion and suggestions for improvements.
Please refer to the current edition of the "IAB Official Protocol
Standards" for the standardization state and status of this protocol.
Distribution of this memo is unlimited.
This document is the outgrowth of a series of meetings of the Privacy
and Security Research Group (PSRG) of the IRTF and the PEM Working
Group of the IETF. I would like to thank the members of the PSRG and
the IETF PEM WG, as well as all participants in discussions on the
"email@example.com" mailing list, for their contributions to this
1. Executive Summary
This document defines message encryption and authentication
procedures, in order to provide privacy-enhanced mail (PEM) services
for electronic mail transfer in the Internet. It is intended to
become one member of a related set of four RFCs. The procedures
defined in the current document are intended to be compatible with a
wide range of key management approaches, including both symmetric
(secret-key) and asymmetric (public-key) approaches for encryption of
data encrypting keys. Use of symmetric cryptography for message text
encryption and/or integrity check computation is anticipated. RFC
1422 specifies supporting key management mechanisms based on the use
of public-key certificates. RFC 1423 specifies algorithms, modes,
and associated identifiers relevant to the current RFC and to RFC
1422. RFC 1424 provides details of paper and electronic formats and
procedures for the key management infrastructure being established in
support of these services.
Privacy enhancement services (confidentiality, authentication,
message integrity assurance, and non-repudiation of origin) are
offered through the use of end-to-end cryptography between originator
and recipient processes at or above the User Agent level. No special
processing requirements are imposed on the Message Transfer System at
endpoints or at intermediate relay sites. This approach allows
privacy enhancement facilities to be incorporated selectively on a
site-by-site or user-by-user basis without impact on other Internet
entities. Interoperability among heterogeneous components and mail
transport facilities is supported.
The current specification's scope is confined to PEM processing
procedures for the RFC-822 textual mail environment, and defines the
Content-Domain indicator value "RFC822" to signify this usage.
Follow-on work in integration of PEM capabilities with othe...