DKIM

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a mechanism by which a Domain Owner can request feedback about email messages using their domain in the From: address field. This document describes "failure reports", or "failed message reports", which provide details about individual messages that failed to authenticate according to the DMARC mechanism.

This document updates RFC 6591 and obsoletes RFC 7489.

Internet mail defines the From: header field to indicate the author of the message's content and the Sender: field to indicate who initially handled the message on the author's behalf. The Sender: field is optional if it has the same information as the From: field. This was not a problem until development of stringent protections on use of the From: field. It has prompted Mediators, such as mailing lists, to modify the From: field to circumvent mail rejection caused by those protections. In effect, the From: field has become dominated by its role as a handling identifier.

The current specification augments the altered use of the From: field by specifying the Author: field, which ensures identification of the original author of the message and is not subject to modification by Mediators. This document is published as an Experimental RFC to assess community interest, functional efficacy, and technical adequacy.

The Authenticated Received Chain (ARC) protocol provides an authenticated "chain of custody" for a message, allowing each entity that handles the message to see what entities handled it before and what the message's authentication assessment was at each step in the handling.

ARC allows Internet Mail Handlers to attach assertions of message authentication assessment to individual messages. As messages traverse ARC-enabled Internet Mail Handlers, additional ARC assertions can be attached to messages to form ordered sets of ARC assertions that represent the authentication assessment at each step of the message-handling paths.

ARC-enabled Internet Mail Handlers can process sets of ARC assertions to inform message disposition decisions, identify Internet Mail Handlers that might break existing authentication mechanisms, and convey original authentication assessments across trust boundaries.

This document specifies a message header field called "Authentication-Results" for use with electronic mail messages to indicate the results of message authentication efforts. Any receiver-side software, such as mail filters or Mail User Agents (MUAs), can use this header field to relay that information in a convenient and meaningful way to users or to make sorting and filtering decisions.

This document obsoletes RFC 7601.

This document adds a new signing algorithm, Ed25519-SHA256, to "DomainKeys Identified Mail (DKIM) Signatures" (RFC 6376). DKIM verifiers are required to implement this algorithm.

The cryptographic algorithm and key size requirements included when DomainKeys Identified Mail (DKIM) was designed a decade ago are functionally obsolete and in need of immediate revision. This document updates DKIM requirements to those minimally suitable for operation with currently specified algorithms.

Domain-based Message Authentication, Reporting, and Conformance (DMARC) introduces a mechanism for expressing domain-level policies and preferences for email message validation, disposition, and reporting. However, the DMARC mechanism enables potentially disruptive interoperability issues when messages do not flow directly from the author's administrative domain to the final Recipients. Collectively, these email flows are referred to as "indirect email flows". This document describes these interoperability issues and presents possible methods for addressing them.

This document describes a general architecture for a reputation-based service, allowing one to request reputation-related data over the Internet, where "reputation" refers to predictions or expectations about an entity or an identifier such as a domain name. The document roughly follows the recommendations of RFC 4101 for describing a protocol model.

This document defines the format of reputation response data ("reputons"), the media type for packaging it, and definition of a registry for the names of reputation applications and response sets.

This document defines a mechanism to conduct queries for reputation information over the HyperText Transfer Protocol (HTTP) using JavaScript Object Notation (JSON) as the payload meta-format.

This document defines a response set for describing assertions a reputation service provider can make about email identifiers, for use in generating reputons.

This document presents extensions to the DomainKeys Identified Mail (DKIM) specification to allow for detailed reporting of message authentication failures in an on-demand fashion. [STANDARDS-TRACK]

This memo registers an extension report type for the Abuse Reporting Format (ARF), affecting multiple registries, for use in generating receipt-time reports about messages that fail one or more email message authentication checks. [STANDARDS-TRACK]

This experimental specification proposes a modification to DomainKeys Identified Mail (DKIM) allowing advertisement of third-party signature authorizations that are to be interpreted as equivalent to a signature added by the administrative domain of the message's author. This document defines an Experimental Protocol for the Internet community.

DomainKeys Identified Mail (DKIM) permits a person, role, or organization that owns the signing domain to claim some responsibility for a message by associating the domain with the message. This can be an author's organization, an operational relay, or one of their agents. DKIM separates the question of the identity of the Signer of the message from the purported author of the message. Assertion of responsibility is validated through a cryptographic signature and by querying the Signer's domain directly to retrieve the appropriate public key. Message transit from author to recipient is through relays that typically make no substantive change to the message content and thus preserve the DKIM signature.

This memo obsoletes RFC 4871 and RFC 5672. [STANDARDS-TRACK]

DomainKeys Identified Mail (DKIM) allows an ADministrative Management Domain (ADMD) to assume some responsibility for a message. Based on deployment experience with DKIM, this document provides guidance for the use of DKIM with scenarios that include Mailing List Managers (MLMs). This memo documents an Internet Best Current Practice.

This memo updates the registry of properties in Authentication- Results: message header fields to allow relaying of the results of a Vouch By Reference query. [STANDARDS-TRACK]

This memo updates the registry of properties in Authentication- Results: message header fields to allow a multiple-result report to distinguish among one or more cryptographic signatures on a message, thus associating specific results with the signatures they represent. [STANDARDS-TRACK]

DomainKeys Identified Mail (DKIM) allows an organization to claim responsibility for transmitting a message, in a way that can be validated by a recipient. The organization can be the author's, the originating sending site, an intermediary, or one of their agents. A message can contain multiple signatures, from the same or different organizations involved with the message. DKIM defines a domain-level digital signature authentication framework for email, using public key cryptography and using the domain name service as its key server technology. This permits verification of a responsible organization, as well as the integrity of the message content. DKIM will also provide a mechanism that permits potential email signers to publish information about their email signing practices; this will permit email receivers to make additional assessments about messages. DKIM's authentication of email identity can assist in the global control of "spam" and "phishing". This document provides implementation, deployment, operational, and migration considerations for DKIM. This document is not an Internet Standards Track specification; it is published for informational purposes.

DomainKeys Identified Mail (DKIM) defines a domain-level authentication framework for email to permit verification of the source and contents of messages. This document specifies an adjunct mechanism to aid in assessing messages that do not contain a DKIM signature for the domain used in the author's address. It defines a record that can advertise whether a domain signs its outgoing mail as well as how other hosts can access that record. [STANDARDS-TRACK]

This document provides an overview of the DomainKeys Identified Mail (DKIM) service and describes how it can fit into a messaging service. It also describes how DKIM relates to other IETF message signature technologies. It is intended for those who are adopting, developing, or deploying DKIM. DKIM allows an organization to take responsibility for transmitting a message, in a way that can be verified by a recipient. The organization can be the author's, the originating sending site, an intermediary, or one of their agents. A message can contain multiple signatures from the same or different organizations involved with the message. DKIM defines a domain-level digital signature authentication framework for email, using public-key cryptography, with the domain name service as its key server technology (RFC 4871). This permits verification of a responsible organization, as well as the integrity of the message contents. DKIM also enables a mechanism that permits potential email signers to publish information about their email signing practices; this will permit email receivers to make additional assessments about messages. DKIM's authentication of email identity can assist in the global control of "spam" and "phishing". This memo provides information for the Internet community.

This document describes the Vouch By Reference (VBR) protocol. VBR is a protocol for adding third-party certification to email. It permits independent third parties to certify the owner of a domain name that is associated with received mail. [STANDARDS-TRACK]

DomainKeys Identified Mail (DKIM) provides a cryptographic mechanism for domains to assert responsibility for the messages they handle. A related mechanism will allow an administrator to publish various statements about their DKIM signing practices. This document defines requirements for this mechanism, distinguishing between those that must be satisfied (MUST), and those that are highly desirable (SHOULD). This memo provides information for the Internet community.

This document provides an analysis of some threats against Internet mail that are intended to be addressed by signature-based mail authentication, in particular DomainKeys Identified Mail. It discusses the nature and location of the bad actors, what their capabilities are, and what they intend to accomplish via their attacks. This memo provides information for the Internet community.