Adding Acronyms to Simplify Conversations about DNS-Based Authentication of Named Entities (DANE)

During discussions on how to add DNS-Based Authentication of Named Entities (DANE) technology to new protocols and services, people were repeatedly confused as to what the numeric values stood for and even the order of the fields of a TLSA record (note that TLSA is not an acronym but a name). This document updates the IANA registry definition for the TLSA record to add a column containing an acronym for each specified field, in order to reduce confusion. This document does not change the DANE protocol in any way. It is expected that DANE parsers in applications and DNS software can adopt parsing the acronyms for each field.

This document applies to the "DNS-Based Authentication of Named Entities (DANE) Parameters" registry located at <http://www.iana.org/assignments/dane-parameters>. IANA has added a column with an acronym to each of the sub-registries. and this document are the referenced documents for the three sub-registries. As these acronyms are offered for human consumption, case does not matter; it is expected that software that parses TLSA records will handle upper-, mixed-, or lower-case use as input.

The reference for this registry has been updated to include both [RFC6698] and this document. Value Acronym Short Description Reference 0 PKIX-TA CA constraint 1 PKIX-EE Service certificate constraint 2 DANE-TA Trust anchor assertion 3 DANE-EE Domain-issued certificate 4-254 Unassigned 255 PrivCert Reserved for Private Use

The reference for this registry has been updated to include both [RFC6698] and this document. Value Acronym Short Description Reference 0 Cert Full certificate 1 SPKI SubjectPublicKeyInfo 2-254Unassigned 255PrivSelReserved for Private Use

The reference for this registry has been updated to include both [RFC6698] and this document. Value Acronym Short Description Reference 0 Full No hash used 1 SHA2-256 256 bit hash by SHA2 2 SHA2-512 512 bit hash by SHA2 3-254 Unassigned 255 PrivMatch Reserved for Private Use

Two examples are described below.

_666._tcp.first.example. TLSA PKIX-TA CERT SHA2-512 {blob} _666._tcp.second.example. TLSA DANE-TA SPKI SHA2-256 {blob}

Protocol FOO only allows TLSA records using PKIX-EE and DANE-EE, with selector SPKI, and using SHA2-512.

This document only changes registry fields and does not change the behavior of any protocol. The hope is to reduce confusion, which would lead to better specification and operations.

Scott Schmit offered really good suggestions to decrease the possibility of confusion. Viktor Dukhovni provided comments from the expert point of view. Jim Schaad, Wes Hardaker, and Paul Hoffman provided feedback during WGLC. Dan Romascanu and Tobias Gondrom pointed out a few defects during the IESG last call.