SMTP Service Extension for Secure SMTP over TLS

Abstract

Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

EMFS: Repurposing SMTP and IMAP for Data Storage and Synchronization

“…The prevalence of TLS-secured open email protocols is also advantageous, as EMFS may take advantage of the existing email security and privacy infrastructure instead of implementing its own. In particular, STARTTLS for both SMTP and IMAP [16,17] is universally supported by large email providers. Beyond transit security, an implementation of the open Pretty Good Privacy (PGP) standard [18] can be used to ensure storage security.…”

Email

“…An alternative mechanism, STARTTLS [18] (an SMTP service extension), is used to 'upgrade' an existing, unprotected TCP connection to a TLS-based, protected TCP connection. STARTTLS is also available in many IMAP and POP implementations, usually in the form of an advertised capacity, with 'sensitive' features, such as authentication, becoming available only after successfully establishing encryption for the existing connection first.…”

Transport Layer Security over Stream Control Transmission Protocol

“…The exception to this rule is for protocols which contain upgrade-to-TLS mechanisms, such as those of HTTP upgrade [RFC2817] and SMTP over TLS [RFC3207]. …”