Mail User Agent Strict Transport Security (MUA-STS)

The information below is for an old version of the document
Document Type Expired Internet-Draft (uta WG)
Last updated 2017-01-09 (latest revision 2016-07-08)
Stream IETF
Intended RFC status (None)
Expired & archived
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Stream WG state WG Document
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IESG IESG state Expired
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This specification defines a set of requirements and facilities designed to improve email confidentiality between a mail user agent (MUA) and a mail submission or mail access server. This provides mechanisms intended to increase use of already deployed Transport Layer Security (TLS) technology and provides a model for a mail user agent's confidentiality assurance. This enables mail service providers to advertise strict transport security (STS) policies that request MUAs increase confidentiality assurance.


Keith Moore (
Chris Newman (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)