DANE

A number of protocols exist for establishing encrypted channels between SMTP Mail Transfer Agents (MTAs), including STARTTLS, DNS- Based Authentication of Named Entities (DANE) TLSA, and MTA Strict Transport Security (MTA-STS). These protocols can fail due to misconfiguration or active attack, leading to undelivered messages or delivery over unencrypted or unauthenticated channels. This document describes a reporting mechanism and format by which sending systems can share statistics and specific information about potential failures with recipient domains. Recipient domains can then use this information to both detect potential attacks and diagnose unintentional misconfigurations.

This specification outlines current recommendations for the use of Transport Layer Security (TLS) to provide confidentiality of email traffic between a Mail User Agent (MUA) and a Mail Submission Server or Mail Access Server. This document updates RFCs 1939, 2595, 3501, 5068, 6186, and 6409.

This document describes how to use secure DNS to associate an S/MIME user's certificate with the intended domain name, similar to the way that DNS-Based Authentication of Named Entities (DANE), RFC 6698, does for TLS.

OpenPGP is a message format for email (and file) encryption that lacks a standardized lookup mechanism to securely obtain OpenPGP public keys. DNS-Based Authentication of Named Entities (DANE) is a method for publishing public keys in DNS. This document specifies a DANE method for publishing and locating OpenPGP public keys in DNS for a specific email address using a new OPENPGPKEY DNS resource record. Security is provided via Secure DNS, however the OPENPGPKEY record is not a replacement for verification of authenticity via the "web of trust" or manual verification. The OPENPGPKEY record can be used to encrypt an email that would otherwise have to be sent unencrypted.

This document clarifies and updates the DNS-Based Authentication of Named Entities (DANE) TLSA specification (RFC 6698), based on subsequent implementation experience. It also contains guidance for implementers, operators, and protocol developers who want to use DANE records.

This memo describes a downgrade-resistant protocol for SMTP transport security between Message Transfer Agents (MTAs), based on the DNS-Based Authentication of Named Entities (DANE) TLSA DNS record. Adoption of this protocol enables an incremental transition of the Internet email backbone to one using encrypted and authenticated Transport Layer Security (TLS).

The DNS-Based Authentication of Named Entities (DANE) specification (RFC 6698) describes how to use TLSA resource records secured by DNSSEC (RFC 4033) to associate a server's connection endpoint with its Transport Layer Security (TLS) certificate (thus enabling administrators of domain names to specify the keys used in that domain's TLS servers). However, application protocols that use SRV records (RFC 2782) to indirectly name the target server connection endpoints for a service domain name cannot apply the rules from RFC 6698. Therefore, this document provides guidelines that enable such protocols to locate and use TLSA records.

This document specifies a new certificate type and two TLS extensions for exchanging raw public keys in Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS). The new certificate type allows raw public keys to be used for authentication.

Experience has shown that people get confused when discussing the three numeric fields of the TLSA record. This document specifies descriptive acronyms for the three numeric fields in TLSA records. This document updates the format of the IANA registry created by RFC 6698.

Encrypted communication on the Internet often uses Transport Layer Security (TLS), which depends on third parties to certify the keys used. This document improves on that situation by enabling the administrators of domain names to specify the keys used in that domain's TLS servers. This requires matching improvements in TLS client software, but no change in TLS server software. [STANDARDS-TRACK]

Many current applications use the certificate-based authentication features in Transport Layer Security (TLS) to allow clients to verify that a connected server properly represents a desired domain name. Typically, this authentication has been based on PKIX certificate chains rooted in well-known certificate authorities (CAs), but additional information can be provided via the DNS itself. This document describes a set of use cases in which the DNS and DNS Security Extensions (DNSSEC) could be used to make assertions that support the TLS authentication process. The main focus of this document is TLS server authentication, but it also covers TLS client authentication for applications where TLS clients are identified by domain names. [STANDARDS-TRACK]