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NIST SP 800-177 (Initial Public Draft)

Trustworthy Email

Date Published: March 2016
Comments Due: April 29, 2016 (public comment period is CLOSED)
Email Questions to: SP800-177@nist.gov


Scott Rose (NIST), Stephen Nightingale (NIST), Simson Garfinkel (NIST), Ramaswamy Chandramouli (NIST)


NIST requests comments on the second draft of Special Publication (SP) 800-177, Trustworthy Email. This draft is a complementary guide to NIST SP 800-45, Guidelines on Electronic Mail Security, and covers protocol security technologies to secure email transactions. This draft guide includes recommendations for the deployment of domain-based authentication protocols for email as well as end-to-end cryptographic protection for email contents. Technologies recommended in support of core Simple Mail Transfer Protocol (SMTP) and the Domain Name System (DNS) include mechanisms for authenticating a sending domain (Sender Policy Framework (SPF), Domain Keys Identified Mail (DKIM) and Domain based Message Authentication, Reporting and Conformance (DMARC). Email content security is facilitated through encryption and authentication of message content using S/MIME and/or Transport Layer Security (TLS) with SMTP. This guide is written for federal agency email administrators, information security specialists and network managers, but contains general recommendations for all enterprise email administrators.



Simple Mail Transfer Protocol (SMTP); Transport Layer Security (TLS); Sender Policy Framework (SPF); Domain Keys Identified Mail (DKIM); Domain based Message Authentication; Reporting and Conformance (DMARC); Domain Name System (DNS) Authentication of Named Entities (DANE); S/MIME; email; OpenPGP
Control Families

System and Communications Protection


Second Draft SP 800-177 (pdf)

Supplemental Material:
Comment Template (xlsx)
First Draft SP 800-177 (pdf)

Document History:
03/30/16: SP 800-177 (Draft)
09/07/16: SP 800-177 (Final)