RFC 1113 (rfc1113) - Page 2 of 34
Privacy enhancement for Internet electronic mail: Part I - message encipherment and authentication procedures
Alternative Format: Original Text Document
RFC 1113 Mail Privacy: Procedures August 1989 4.6.1 Per-Message Encapsulated Header Fields 20 4.6.1.1 X-Proc-Type Field 20 4.6.1.2 X-DEK-Info Field 21 4.6.2 Encapsulated Header Fields Normally Per-Message 21 4.6.2.1 X-Sender-ID Field 22 4.6.2.2 X-Certificate Field 22 4.6.2.3 X-MIC-Info Field 23 4.6.3 Encapsulated Header Fields with Variable Occurrences 23 4.6.3.1 X-Issuer-Certificate Field 23 4.6.4 Per-Recipient Encapsulated Header Fields 24 4.6.4.1 X-Recipient-ID Field 24 4.6.4.2 X-Key-Info Field 24 4.6.4.2.1 Symmetric Key Management 24 4.6.4.2.2 Asymmetric Key Management 25 5. Key Management 26 5.1 Data Encrypting Keys (DEKs) 26 5.2 Interchange Keys (IKs) 26 5.2.1 Subfield Definitions 28 5.2.1.1 Entity Identifier Subfield 28 5.2.1.2 Issuing Authority Subfield 29 5.2.1.3 Version/Expiration Subfield 29 5.2.2 IK Cryptoperiod Issues 29 6. User Naming 29 6.1 Current Approach 29 6.2 Issues for Consideration 30 7. Example User Interface and Implementation 30 8. Areas For Further Study 31 9. References 32 NOTES 32 1. Executive Summary This RFC defines message encipherment and authentication procedures, in order to provide privacy enhancement services for electronic mail transfer in the Internet. It is one member of a related set of four RFCs. The procedures defined in the current RFC 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-1114 specifies supporting key management mechanisms based on the use of public-key certificates. RFC-1115 specifies algorithm and related information relevant to the current RFC and to RFC-1114. A subsequent RFC will provide 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, and Linn
