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: 2019-Feb-10
Internet Society Requests For Comment (RFCs)
This document defines message encryption and authentication procedures, in order to provide privacy-enhanced mail (PEM) services for electronic mail transfer in the Internet. [STANDARDS-TRACK]
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 "firstname.lastname@example.org" mailing list, for their contributions to this document.
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
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RFC 1421 Privacy Enhancement for Electronic Mail February 1993
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 other messaging environments (e.g., MIME) is anticipated and will be addressed in separate and/or successor documents, at which po...