RDAP Extension for Structured Reliability Assessment Metadata
draft-bertoldi-regext-rdap-reliability-scoring-03
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Alessandro Bertoldi , Simon Pietro Romano | ||
| Last updated | 2026-09-13 | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
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draft-bertoldi-regext-rdap-reliability-scoring-03
REGEXT A. Bertoldi
Internet-Draft Bertoldi Cybersecurity
Intended status: Experimental S. P. Romano
Expires: 17 March 2027 UNINA
13 September 2026
RDAP Extension for Structured Reliability Assessment Metadata
draft-bertoldi-regext-rdap-reliability-scoring-03
Abstract
This document proposes an extension to the Registration Data Access
Protocol (RDAP) that enables the representation and exchange of
structured reliability assessment metadata for registrars and domain
names. The extension defines a structured assessment envelope
through which an RDAP server can expose assessment results produced
by a registry, registrar, or third-party assessor in a common,
machine-readable format within RDAP responses.
The extension standardizes how assessment results are transported and
referenced, not how they are computed. Scoring methodologies,
thresholds, criteria, and governance frameworks are intentionally
left to the operational and policy layer. This document does,
however, place requirements on the specification of any scheme whose
results are intended for publication through RDAP, because publishing
an evaluative judgement about an identified party without safeguards
for notification, remediation, and contestation is not a safe
practice.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 17 March 2027.
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Copyright Notice
Copyright (c) 2026 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. What Distinguishes This Extension . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Motivation and Problem Statement . . . . . . . . . . . . . . 5
3.1. Assessment as an Instrument for Both Directions . . . . . 6
3.2. Relationship to Periodic Certification . . . . . . . . . 6
3.3. Why Protocol-Level Representation Helps . . . . . . . . . 6
4. Design Principles . . . . . . . . . . . . . . . . . . . . . . 7
5. Deployment Model . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Deployment Configurations . . . . . . . . . . . . . . . . 8
5.2. Minimal Response . . . . . . . . . . . . . . . . . . . . 8
5.3. Endpoint Discovery . . . . . . . . . . . . . . . . . . . 9
5.4. Referral from an Authoritative Server . . . . . . . . . . 9
6. Subject Binding . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Domains . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.2. Registrars . . . . . . . . . . . . . . . . . . . . . . . 10
6.3. Known Limitations . . . . . . . . . . . . . . . . . . . . 10
7. RDAP Extension: Data Model . . . . . . . . . . . . . . . . . 11
7.1. Extension Identifier . . . . . . . . . . . . . . . . . . 11
7.2. Extension Version Identifier . . . . . . . . . . . . . . 11
7.3. Namespacing Approach . . . . . . . . . . . . . . . . . . 12
7.4. Assessment Envelope . . . . . . . . . . . . . . . . . . . 12
7.5. Field Definitions . . . . . . . . . . . . . . . . . . . . 12
7.6. Result Status Values . . . . . . . . . . . . . . . . . . 15
7.7. Scheme Stability . . . . . . . . . . . . . . . . . . . . 15
7.8. Absence of the Member . . . . . . . . . . . . . . . . . . 16
7.9. Registrar Object Extension . . . . . . . . . . . . . . . 16
7.10. Domain Object Extension . . . . . . . . . . . . . . . . . 17
8. Requirements on Scoring Scheme Specifications . . . . . . . . 18
9. Relationship to Existing Work . . . . . . . . . . . . . . . . 19
9.1. Relationship to
draft-loffredo-regext-rdap-verified-contacts . . . . . . 19
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9.2. Relationship to PIR Abuse Intervention Program . . . . . 19
9.3. Relationship to RDAP Core Specifications . . . . . . . . 20
10. Applicability and Implementation Status . . . . . . . . . . . 20
11. Security Considerations . . . . . . . . . . . . . . . . . . . 20
11.1. Provenance and Authenticity . . . . . . . . . . . . . . 22
12. Privacy Considerations . . . . . . . . . . . . . . . . . . . 23
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
13.1. RDAP Extensions Registry . . . . . . . . . . . . . . . . 24
13.2. RDAP JSON Values Registry . . . . . . . . . . . . . . . 25
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
14.1. Normative References . . . . . . . . . . . . . . . . . . 25
14.2. Informative References . . . . . . . . . . . . . . . . . 26
Appendix A. Changes from -02 . . . . . . . . . . . . . . . . . . 28
A.1. Registration . . . . . . . . . . . . . . . . . . . . . . 28
A.2. Corrections . . . . . . . . . . . . . . . . . . . . . . . 29
A.3. Technical corrections . . . . . . . . . . . . . . . . . . 29
A.4. Changes from -01, retained for continuity . . . . . . . . 30
A.5. Breaking Changes . . . . . . . . . . . . . . . . . . . . 30
A.6. Additions . . . . . . . . . . . . . . . . . . . . . . . . 31
A.7. Corrections . . . . . . . . . . . . . . . . . . . . . . . 31
A.8. Deferred . . . . . . . . . . . . . . . . . . . . . . . . 32
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 32
Appendix C. Example RDAP Responses . . . . . . . . . . . . . . . 32
C.1. Domain Lookup with a Single Result . . . . . . . . . . . 32
C.2. Registrar Lookup with Results from Two Issuers . . . . . 33
C.3. Domain Lookup without Assessment Metadata . . . . . . . . 34
Appendix D. Illustrative Assessment Dimensions . . . . . . . . . 35
D.1. Possible Registrar Assessment Dimensions . . . . . . . . 35
D.2. Possible Domain Assessment Dimensions . . . . . . . . . . 36
D.3. Note on Existing Operational Programs . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36
1. Introduction
The domain registration ecosystem relies on registrars as critical
intermediaries between domain owners and the global DNS
infrastructure. Research [DEEPSEC2025] has identified recurring
systemic vulnerabilities in registrar processes, including credential
recovery, identity verification, and email authentication
configurations, that represent structural risks affecting large
numbers of domains and their owners. These issues have in several
cases remained unaddressed for extended periods despite responsible
disclosure.
The Registration Data Access Protocol (RDAP), defined in [RFC7480],
[RFC7481], [RFC9082], [RFC9083], and [RFC9224], was designed as the
successor to WHOIS and introduces structured JSON responses,
authentication and authorization support, and a well-defined
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extensibility model. These properties make RDAP a suitable
foundation for exposing structured security and reliability metadata
in a standardized, interoperable way.
This document defines an RDAP extension that provides an envelope for
carrying assessment results related to the security posture and
reliability of registrars and domain names. The extension
standardizes the transport and referencing of such results; it does
not define scoring methodologies, thresholds, or enforcement
mechanisms. The protocol enables representation; the ecosystem
decides how to populate and consume the exposed fields.
The proposal is intended as complementary to
[I-D.loffredo-regext-rdap-verified-contacts], which allows the
inclusion of verification status information for contact fields,
indicating which pieces of contact data have been verified and how.
The present extension adds a parallel layer: structured metadata
about the security posture of the registrar and the domain itself.
1.1. What Distinguishes This Extension
Unlike most registration data fields, this extension carries
evaluative metadata whose interpretation and consequences depend on a
methodology and an issuer external to the RDAP server. This creates
materially different considerations regarding provenance,
contestation, staleness, and disclosure than those that apply to
registration data held by the responding authority. The remainder of
this document is shaped by that difference.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The following terms are used throughout this document:
Assessment Result: The structured set of fields defined by this
extension representing a single result of a security or
reliability assessment of a registrar or domain, produced by one
issuer under one scheme. A result carries the outcome and points
to the methodology; it does not define the methodology itself.
Assessment Envelope: The array of assessment results carried by the
JSON member defined by this extension.
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Score Scheme: An identifier or URI that denotes the scoring
methodology used to produce an assessment result. The scheme
defines the semantics of the result, its range, and its criteria.
Scheme definitions are maintained externally to this document.
Score Issuer: A globally unique and stable identifier for the entity
that performed the assessment and produced the result.
Assessed Party: The registrar or domain that is the subject of an
assessment result.
Assessment Service: An RDAP service that publishes assessment
results and is not authoritative for the registration data of the
assessed party.
Extension Identifier: The RDAP extension string that identifies this
extension in the IANA RDAP Extensions Registry.
3. Motivation and Problem Statement
Research [DEEPSEC2025] has identified recurring systemic
vulnerabilities in domain registrar processes that cannot be
addressed by conventional technical security controls. These
vulnerabilities arise from weaknesses in the interface between
digital systems and human processes, and include deficiencies in
credential recovery, identity verification, and email authentication
configurations.
A notable characteristic of these vulnerabilities is their
persistence: in several documented cases, exploitable issues remained
unresolved for extended periods following responsible disclosure,
reflecting diffuse accountability and the absence of structured
incentives for timely remediation.
These findings suggest that while technical standards such as SPF
[RFC7208], DKIM [RFC6376], and DMARC [RFC9989] are sound, their
adoption and correct configuration cannot be reliably ensured without
structured, machine-readable signaling mechanisms. The full
technical details of the underlying research are documented in
[DEEPSEC2025].
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3.1. Assessment as an Instrument for Both Directions
A published assessment is not only exposure for a party that is
managed poorly. It is equally a means by which a well-run operator
can demonstrate its posture in a form that a third party can verify
and consume automatically. The absence of such a mechanism today
means that operators who invest in security have no interoperable way
to make that investment legible, and that operators who do not have
no structured incentive to change. Both effects are addressed by the
same mechanism.
3.2. Relationship to Periodic Certification
Certification and operational assessment address different needs and
are complementary rather than alternative.
Certification against a standard such as ISO/IEC 27001 [ISO27001] or
ISO/IEC 27701 [ISO27701] attests conformity within a defined scope at
a point in time, through a formal audit, and where the certification
body is accredited it carries the assurance of that accreditation.
An operational assessment can instead represent finer-grained
technical and procedural properties that change over time, such as
how credential recovery is handled or how email authentication is
configured on operator-controlled domains.
The intent of this document is not to displace certification, but to
complement it with a representation capable of expressing a more
frequent and more current view of security posture than a periodic
certification cycle can provide. Nothing in this document should be
read as suggesting that an assessment result is equivalent to, or a
substitute for, a certification.
3.3. Why Protocol-Level Representation Helps
Structured representation of assessment metadata at the protocol
level offers several complementary benefits relative to existing
operational approaches.
First, machine-readable assessment data, where its publication is
appropriate, creates reputational and commercial incentives for
registrars and domain owners to adopt and maintain security best
practices.
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Second, a standardized RDAP extension enables any registry,
registrar, browser, or security tool to consume assessment metadata
through a common interface, eliminating dependency on proprietary or
registry-specific systems. The alternative, in practice, is each
assessor publishing its own HTTP interface with its own object model
and query syntax.
Third, protocol-level representation does not replace operational
scoring or enforcement programs. Rather, it provides a standardized
channel through which the outputs of such programs can be expressed
and consumed by the broader ecosystem.
4. Design Principles
The following principles guide the design of this extension.
Separation of concerns: This document defines the structured
assessment envelope and extension points. The governance of who
computes results, the specific methodology, any thresholds
applied, and any enforcement actions based on results belong to
the operational and policy layer and are outside the scope of this
document. The requirements in Section 8 are the single deliberate
exception, and are requirements on a scheme specification rather
than on an RDAP server.
Envelope, not methodology: The extension standardizes how assessment
results are transported and referenced within RDAP. It does not
standardize how assessments are performed, what criteria are
evaluated, or what thresholds apply.
Response extension, not query extension: This document defines no
new query, no new path segment, and no new query parameter. It
extends responses only.
Extensibility: The extension is designed to accommodate additional
fields without breaking backward compatibility, consistent with
RDAP's existing extensibility model.
Interoperability: The extension is not tied to any specific
registry, registrar, or policy framework. Any conformant RDAP
server may implement it independently.
Complementarity: The extension is designed to coexist with and
complement [I-D.loffredo-regext-rdap-verified-contacts], rather
than replace or duplicate it.
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5. Deployment Model
The -01 revision of this document described no deployment model.
Discussion at IETF 126 made clear that this was the principal gap,
and this section responds to it.
5.1. Deployment Configurations
Three configurations are anticipated.
Assessment service: An RDAP service operated by the assessor,
distinct from any authority for the registration data of the
assessed party. This is the primary configuration anticipated by
this document.
Republication: A registry, registrar, or other RDAP server that
publishes an assessment result produced by a third party. This
configuration introduces an intermediary and is discussed in
Section 11.1.
Self-assessment: An operator publishing an assessment of itself.
This remains possible, but the identity of the issuer conveyed in
"scoreIssuer" allows a consumer to recognise the configuration and
to weigh the result accordingly.
5.2. Minimal Response
Clients MUST NOT treat an assessment service as authoritative for the
registration data of the assessed object.
An assessment service SHOULD return only the members required to bind
the response to the assessed object, together with the member defined
by this extension. For a domain object this is "objectClassName" and
"ldhName"; for an entity object it is "objectClassName", "handle",
and, where applicable, "publicIds" and "roles". The
"rdapConformance" member is required by [RFC9083].
The list above does not include a "self" link. [RFC9083] states that
a server SHOULD provide a link identifying the object class instance
itself, and an assessment service that can provide one SHOULD do so:
the purpose of this section is to limit the registration data that an
assessment service restates, not to suppress a link that identifies
the object at the assessment service.
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An assessment service SHOULD NOT mirror the registration data
returned by the authoritative server and enrich it with assessment
metadata. Such a pattern would place the assessment service in the
position of restating registration data for which it has no authority
and no update path, and it is not a requirement of this document.
5.3. Endpoint Discovery
The bootstrap mechanism defined in [RFC9224] determines the
authoritative server for the scopes it covers, being domain names, IP
addresses, and Autonomous System numbers. Section 9 of [RFC9224]
states that entities are not bootstrapped by that mechanism, and
Section 6 of that document points instead to [RFC8521]. An
assessment service is not authoritative for registration data in any
of those scopes, and this document therefore does not place
assessment services in that bootstrap and does not define a parallel
one.
Where a consumer has established trust in an issuer out of band, the
endpoint of that issuer's assessment service is provisioned as part
of the same trust configuration, and no separate discovery mechanism
is required. A consumer that has not established such trust has no
basis on which to act on a result in any case, as discussed in
Section 11.1.
5.4. Referral from an Authoritative Server
The authors considered, and do not propose, a mechanism by which an
authoritative RDAP server would point at an assessment service using
a "links" member with the "related" relation.
The "related" relation is already used for registry-to-registrar
referrals. Reusing it for this purpose would require precise
semantics, an expected media type, and clear client processing rules.
Defining a new relation would require its registration. In either
case, a link published by the authoritative server could reasonably
be read as an endorsement of the assessor, which is not a property
this document intends to create.
6. Subject Binding
An assessment result is only meaningful if the object it is attached
to can be bound unambiguously to the assessed party.
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6.1. Domains
For domain objects, "ldhName" provides the standard lookup key and
the query form /domain/<ldhName> defined in [RFC9082] works
unchanged. No additional mechanism is required.
6.2. Registrars
For entity objects the situation is less straightforward. [RFC9082]
defines entity lookup as /entity/<handle> (Section 3.1.5), where the
syntax of a handle is specific to the registration provider, and
entity search as /entities?fn= and /entities?handle= (Section 3.2.3).
Neither search key is an IANA Registrar ID. The "publicIds" member,
which is where such an identifier would be carried, is a response
structure and is neither a lookup key nor a defined search key.
An assessment service SHOULD use its own service-local handle for
/entity/<handle> lookups, and SHOULD include a "publicIds" member
binding that local object to the assessed registrar, for example
through the applicable IANA Registrar ID.
This document deliberately does not define a lookup by IANA Registrar
ID. Doing so would convert this extension from a response extension
into a query extension, with the consequences described in
Section 2.3 of [I-D.ietf-regext-rdap-extensions], and the authors do
not consider it warranted at this stage.
6.3. Known Limitations
Two assessors will use different local handles for the same
registrar, and "publicIds" supplies the binding only after the object
has been retrieved. A client that holds an IANA Registrar ID and
wishes to locate the corresponding object at a known assessment
service therefore has no in-band means of constructing the query.
Object tagging [RFC8521] can bootstrap an entity query where a client
already holds a tagged handle whose suffix identifies the RDAP
service provider. One conceivable profile would use the IANA
Registrar ID as the local portion of the handle and the assessor's
registered provider tag as its suffix, making the full handle
derivable once the assessor is known out of band. The authors raise
this as an open question rather than proposing it: it is not clear
whether this is a sound use of [RFC8521] given that the assessor
would be authoritative for the assessment representation but not for
the underlying registration data. Feedback is explicitly sought.
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The binding for registrars operating under ccTLD registries, and for
registrars with no IANA Registrar ID, is likewise unresolved. The
"publicIds" member accommodates other identifier types, but this
document does not prescribe one.
7. RDAP Extension: Data Model
7.1. Extension Identifier
This extension is identified by the string "reliabilityAssessment",
to be registered in the IANA RDAP Extensions Registry (see
Section 13). RDAP responses that include this extension MUST include
the extension identifier in the "rdapConformance" array.
Consistent with Section 2.2 of [I-D.ietf-regext-rdap-extensions], the
extension identifier contains no underscore character. The JSON
member defined by this extension is prefixed with the extension
identifier, avoiding the bare extension identifier pattern discussed
in that section.
7.2. Extension Version Identifier
Section 5.4 of [I-D.ietf-regext-rdap-extensions] states that RDAP
extension identifiers are opaque and that extensions without an
explicitly defined versioning scheme are opaquely versioned. This
extension defines no such scheme, and is therefore opaquely
versioned.
Section 6.1 of [I-D.ietf-regext-rdap-versioning] provides that all
extensions support Opaque Versioning by default and that an extension
document should identify the versioning types it supports together
with the associated extension version identifier. Accordingly:
Versioning type: Opaque Versioning, as described in Section 5.1 of
[I-D.ietf-regext-rdap-versioning].
Extension version identifier: reliabilityAssessment
This document does not use Point Versioning. It defines a single
version of a single extension, and the machinery for negotiating
concurrent versions is not warranted at this stage. Nothing in this
choice precludes the later adoption of Point Versioning: an extension
supporting another versioning type may still be referred to using
Opaque Versioning.
Implementation of [I-D.ietf-regext-rdap-versioning] is not required
in order to implement this extension, and this document places no
such requirement on clients or servers.
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Consistent with Section 5.4 of [I-D.ietf-regext-rdap-extensions], any
change to this extension that is not backward compatible will require
the registration of a new extension identifier and a new
specification.
7.3. Namespacing Approach
This extension groups all its fields under a single top-level JSON
member named "reliabilityAssessment_results". The member name is
prefixed with the extension identifier, while the members of the
objects it contains (scoreScheme, scoreValue, and so on) are not
individually prefixed. This follows the guidance in Section 2.4.2 of
[I-D.ietf-regext-rdap-extensions], which states that prefixing is not
required for children of a prefixed JSON object defined by an RDAP
extension.
7.4. Assessment Envelope
The "reliabilityAssessment_results" member contains a JSON array of
assessment result objects. This member MAY appear within entity
objects (objectClassName: "entity") and domain objects
(objectClassName: "domain"). An entity is considered to represent a
registrar when its "roles" array includes the value "registrar" as
defined in Section 10.2.4 of [RFC9083].
If the member is present, the array MUST contain at least one
element. The order of elements is not significant, and clients MUST
NOT infer precedence, authority, or recency from position. Clients
MUST NOT assume that the array contains exactly one element.
A server SHOULD publish at most one current result for any given
combination of "scoreScheme" and "scoreIssuer".
Each result carries the outcome of an external assessment and points
to the methodology used. It does not define the methodology, the
criteria, or the thresholds.
7.5. Field Definitions
The members of each assessment result object are described in the
following table.
+===============+=============+====================================+
| Field | Type | Description |
+===============+=============+====================================+
| scoreScheme | string | REQUIRED. Identifies the |
| | | methodology used to produce the |
| | | result. It SHOULD be a URI |
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| | | conforming to [RFC3986]. An HTTPS |
| | | URI under a domain the issuer |
| | | controls is the form this document |
| | | recommends, because the domain |
| | | gives the issuer a name space in |
| | | which it can assign scheme |
| | | identifiers without colliding with |
| | | those of another issuer, and |
| | | because the scheme definition may |
| | | also be made retrievable at that |
| | | address. Another URI form that |
| | | provides an equivalent delegated |
| | | name space, such as a URN under a |
| | | registered namespace identifier, |
| | | serves the same purpose. Neither |
| | | [RFC3986] nor this document |
| | | requires a URI to be |
| | | dereferenceable. Where it is not |
| | | a URI it is an opaque string whose |
| | | meaning is defined solely by the |
| | | issuer identified in |
| | | "scoreIssuer", and it MUST NOT be |
| | | assumed to be unique outside that |
| | | issuer. The scheme defines the |
| | | semantics, range, and criteria of |
| | | the result. Scheme definitions |
| | | are maintained externally. |
+---------------+-------------+------------------------------------+
| scoreIssuer | string | REQUIRED. Identifies the entity |
| | (URI) | that performed the assessment and |
| | | issued the result. It MUST be a |
| | | URI conforming to [RFC3986], |
| | | globally unique and stable, and |
| | | SHOULD be under the control of the |
| | | issuer. |
+---------------+-------------+------------------------------------+
| scoreValue | number | OPTIONAL. The non-negative |
| | | numeric result of the assessment, |
| | | as defined by the scoreScheme. If |
| | | scoreMaxValue is present, |
| | | scoreValue MUST NOT exceed it. |
+---------------+-------------+------------------------------------+
| scoreMaxValue | number | OPTIONAL. The non-negative upper |
| | | bound of the range defined by the |
| | | scoreScheme. Together with |
| | | scoreValue it allows a consumer to |
| | | interpret the numeric result |
| | | without resolving the scheme. A |
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| | | scheme whose results are not |
| | | bounded omits this member. |
+---------------+-------------+------------------------------------+
| scoreDate | string | OPTIONAL. The date and time at |
| | (date-time) | which the assessment was |
| | | performed, in the format defined |
| | | in [RFC3339]. |
+---------------+-------------+------------------------------------+
| validUntil | string | OPTIONAL. The date and time after |
| | (date-time) | which the issuer no longer asserts |
| | | the result as current, in the |
| | | format defined in [RFC3339]. Its |
| | | expiry does not render the result |
| | | invalid; it indicates that the |
| | | issuer does not vouch for its |
| | | currency beyond that point. |
+---------------+-------------+------------------------------------+
| assessmentId | string | OPTIONAL. An identifier for this |
| | | specific result, unique within the |
| | | scope of the combination of |
| | | scoreScheme and scoreIssuer. It |
| | | allows a specific result to be |
| | | referenced, in particular in a |
| | | contestation or correction |
| | | process. |
+---------------+-------------+------------------------------------+
| status | string | OPTIONAL. The lifecycle state of |
| | | the result as asserted by the |
| | | issuer. Permitted values are |
| | | defined in Section 7.6. |
+---------------+-------------+------------------------------------+
| evidenceUri | string | OPTIONAL. A URI pointing to |
| | (URI) | supporting documentation, a |
| | | detailed report, or the full |
| | | assessment record maintained by |
| | | the scoreIssuer. |
+---------------+-------------+------------------------------------+
Table 1
A member for which no value is available is omitted rather than being
included with a null value.
If "scoreValue" is present, "scoreDate" SHOULD also be present, so
that the result can be situated in time. If "scoreMaxValue" is
present, "scoreValue" SHOULD also be present.
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The field values used in the examples in this document and in
Appendix C are illustrative and carry no normative meaning. Each
example is to be read as if retrieved shortly after the time given in
its "scoreDate".
Where "scoreScheme" and "scoreIssuer" are compared, for example to
determine whether two results were produced by the same issuer under
the same scheme, they are compared as strings, character by
character, without any URI normalization. An issuer that publishes
results is therefore expected to use one consistent spelling of each
value. Section 6 of [RFC3986] describes why URI equivalence is
otherwise application-dependent.
7.6. Result Status Values
The "status" member, when present, takes one of the following values:
active: The issuer asserts the result as current.
under review: The result is the subject of a review or contestation
process, and the issuer indicates that it may change. Consumers
SHOULD treat a result in this state with additional caution.
withdrawn: The issuer no longer asserts the result. A withdrawn
result MAY continue to be published so that consumers holding a
cached copy can observe the withdrawal.
The absence of the "status" member means that the issuer does not
convey a lifecycle state. Consumers MUST NOT assume a value of
"active" in that case.
These values are scoped to the "status" member of an assessment
result object as defined by this extension. They are distinct from,
and do not interact with, the RDAP status values defined in
Section 10.2.2 of [RFC9083]. This document does not define a
supersession mechanism. A server that publishes only current results
does not require one, and the publication of assessment history is
outside the scope of this document.
7.7. Scheme Stability
If all semantics of a result are defined outside this protocol, the
identity of the scheme must be stable for those semantics to be
resolvable.
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The semantics associated with a given "scoreScheme" identifier MUST
NOT change in a manner that is not backward compatible. A revision
of a scheme that is not backward compatible MUST be assigned a new
scheme identifier.
7.8. Absence of the Member
Clients MUST NOT interpret the absence of the
"reliabilityAssessment_results" member as evidence that the object
has not been assessed, nor as a negative assessment of the object.
The member may be absent because the object has not been assessed,
because it has been assessed but the result is not published, because
publication is withheld under server policy, because the data is
subject to access control and the client is not authorized, or
because the server does not implement this extension.
This document deliberately defines no signal distinguishing "not
assessed" from "assessed but not disclosed". Such a signal would
defeat the purpose of withholding a result, since it would itself
indicate that there is something to withhold, and would reintroduce
the disclosure risk described in Section 11.
7.9. Registrar Object Extension
The following example illustrates a lookup response for an entity
object representing a registrar, carrying the assessment envelope.
The "rdapConformance" member appears because the example is a
complete response; per Section 4.1 of [RFC9083] it appears only in
the topmost object of a response and never in a nested one.
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{
"rdapConformance": [
"rdap_level_0",
"reliabilityAssessment"
],
"objectClassName": "entity",
"handle": "REGISTRAR-EXAMPLE",
"roles": ["registrar"],
"publicIds": [
{
"type": "IANA Registrar ID",
"identifier": "999999"
}
],
"reliabilityAssessment_results": [
{
"scoreScheme": "https://assessor.example/schemes/registrar/v1",
"scoreIssuer": "https://assessor.example",
"scoreValue": 8,
"scoreMaxValue": 10,
"scoreDate": "2026-01-15T10:30:00Z",
"validUntil": "2026-07-15T00:00:00Z",
"assessmentId": "a-2026-01-15-0042",
"status": "active",
"evidenceUri": "https://assessor.example/rep/a-2026-01-15-0042"
}
]
}
7.10. Domain Object Extension
The following example illustrates a lookup response for a domain
object carrying the assessment envelope.
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{
"rdapConformance": [
"rdap_level_0",
"reliabilityAssessment"
],
"objectClassName": "domain",
"handle": "D-EXAMPLE-1",
"ldhName": "example.com",
"reliabilityAssessment_results": [
{
"scoreScheme": "https://assessor.example/schemes/domain/v2",
"scoreIssuer": "https://assessor.example",
"scoreValue": 7,
"scoreMaxValue": 10,
"scoreDate": "2026-02-01T08:00:00Z",
"status": "active"
}
]
}
8. Requirements on Scoring Scheme Specifications
This document does not define assessment methodologies. It does,
however, place requirements on the specification of a scheme whose
results are intended for publication through RDAP, because publishing
an evaluative judgement about an identified party without safeguards
is not a safe practice, and because this document creates the channel
through which such publication would occur.
A specification defining a "scoreScheme" whose results are intended
for publication through RDAP:
* MUST document a disclosure threat model, describing what an
adversary could learn from the published result and how that risk
is weighed against the benefit of publication;
* MUST define a notification to the assessed party prior to
publication of a result;
* MUST define a period, following that notification and preceding
publication, during which the assessed party may remediate the
findings or contest the result;
* SHOULD define whether a reassessment performed within that period
replaces the pending result, so that a party that remediates
promptly is not exposed by a result that no longer reflects its
posture;
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* MUST describe how data minimization is applied, stating whether
aggregation, coarse granularity, access control, or delayed
publication are used, and why the chosen granularity is
appropriate;
* MUST state whether its results are intended for publication in
respect of domain objects and, if so, MUST justify that choice
specifically against the targeting risk described in Section 11.
This document deliberately does not prescribe the duration of the
remediation and contestation period, the governance of the process,
the body responsible for adjudicating a contestation, or the
consequences of a successful one. Those belong to the scheme and its
operational model.
There is a tension that this document cannot resolve on its own: the
more actionable a signal is for defenders, the more useful it is to
attackers. The requirements above are intended to force each scheme
to confront that tension explicitly rather than to leave it
unexamined.
9. Relationship to Existing Work
9.1. Relationship to draft-loffredo-regext-rdap-verified-contacts
The [I-D.loffredo-regext-rdap-verified-contacts] extension allows the
inclusion of verification status information for contact fields
associated with a domain or registrar, indicating which pieces of
contact data have been verified and how. The present extension adds
a complementary and orthogonal layer: structured metadata about the
security posture of the registrar and the domain itself.
The two extensions answer different questions. The verified-contacts
extension conveys which contact fields have been verified and how the
verification was performed. The reliability assessment extension
addresses what the assessed security posture of the entity managing
that domain is. Both are expressible within the RDAP framework and
are designed to coexist within the same RDAP response.
9.2. Relationship to PIR Abuse Intervention Program
The Public Interest Registry (PIR) publishes a Quality Performance
Index (QPI) [PIR-QPI], and has described an Abuse Intervention
Program [PIR-AIP]. PIR states that QPI is calculated from three core
key performance indicators, named by PIR as Abuse Takedown, Renewal
Rates, and Domain Usage, and three secondary ones, named by PIR as
SSL, DNSSEC, and ATL. PIR states that it has made the QPI program
and algorithm available to all members of the domain industry rather
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than confining them to a single name space.
This document does not standardize such a program; it defines a
generic RDAP representation that could carry outputs produced by
programs such as QPI or other assessment frameworks. An operational
scoring system of this kind could, in principle, expose its outputs
through the envelope defined in this document, enabling broader
interoperability without modifying its internal methodology. The
authors note that PIR has not, to their knowledge, undertaken RDAP
work in connection with these programs.
9.3. Relationship to RDAP Core Specifications
This extension is designed to be fully conformant with the RDAP core
specifications [RFC7480] [RFC7481] [RFC9082] [RFC9083] [RFC9224]. It
uses the JSON response format defined in [RFC9083], the extensibility
model provided in [RFC7480], and the security framework of [RFC7481].
Query formats follow [RFC9082] and are not extended by this document.
10. Applicability and Implementation Status
The authors are aware of no implementation of this extension at the
time of writing, and state this explicitly rather than leave it to be
inferred.
The configurations in which the extension is expected to be useful
are those described in Section 5: an assessment service operated by a
research group, a security vendor, or a sector body; a registry or
registrar republishing a third-party result; and, more marginally,
self-assessment. The consumers anticipated are RDAP clients operated
by registries, registrars, enterprise security teams, and
researchers.
The authors would welcome statements of interest from any party that
operates or plans to operate an assessment program, implements RDAP
clients, or would consume this kind of data. A statement that a
party would not use the extension, together with the reason, is
equally valuable.
11. Security Considerations
The fields defined in this extension are informational. They do not
constitute enforcement mechanisms, and clients MUST NOT treat them as
authoritative security certifications.
Reconnaissance and exposure: A published result indicating a weak
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security posture is itself a signal that may be used to identify
and prioritise targets. The risk increases where the result is
accompanied by the methodology, the assessment date, evidence, or
the specific dimensions that contributed to it. The risk is
materially greater for domain objects than for registrar objects,
since a domain-level result may identify an individual poorly
defended target, whereas a registrar-level result concerns an
accountable operator of scale. Section 8 requires each scheme to
address this explicitly.
Relationship to risk-based regulatory obligations: The Network and
Information Security Directive [NIS2] does not explicitly prohibit
the publication of a security or reliability result concerning a
domain name or a registrar. Article 21(1) does, however, require
Member States to ensure that essential and important entities take
appropriate and proportionate technical, operational and
organisational measures to manage the risks posed to the security
of the network and information systems those entities use, and
Article 21(2) provides that such measures shall include at least a
list of items, among them "policies on risk analysis and
information system security" at point (a) and security in
acquisition, development and maintenance "including vulnerability
handling and disclosure" at point (e). Systematic and
unauthenticated public disclosure of assessment results may be
difficult to reconcile with those obligations where the disclosure
substantially increases the exposure of the assessed entity.
Implementers operating under that framework, or an equivalent one,
should assess the publication of results accordingly. That
directive is not the only regime that may bear on publication:
data protection law, the law of defamation, trade secret
protection, and applicable national law may each constrain the
publication of an evaluative result about an identified party.
Perception as a rating: An assessment result may be read as a rating
of the assessed party, with consequent reputational, commercial,
and legal exposure, irrespective of the intent of the scheme that
produced it. Publication is therefore not a neutral act, and
Section 8 places requirements on schemes accordingly.
Volatility: A result may change quickly. A value published today
may be higher or lower tomorrow, and a consumer acting on a result
may be acting on a state of affairs that no longer holds. The
"validUntil" and "status" members provide partial mitigation but
do not eliminate this.
Access control and server policy: Publication of assessment metadata
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is not mandatory. A server MAY expose this extension only to
authenticated and authorized clients, and MAY apply different
policies to registrar and domain objects. Nothing in this
document requires that assessment metadata be publicly accessible.
Inference from absence: See Section 7.8. The absence of assessment
metadata is not evidence of anything, and clients MUST NOT treat
it as such.
Result integrity: This document does not define an interface for
creating or modifying assessment metadata. Any administrative or
provisioning interface used for that purpose MUST authenticate and
authorize the submitting entity and MUST provide appropriate
integrity and confidentiality protection. Without authentication
of the issuing entity, assessment metadata is susceptible to
manipulation.
Gaming and abuse: Any visible scoring system creates incentives for
gaming. The governance framework, which is outside the scope of
this document, is expected to address verification, audit, and
revocation mechanisms.
False assurance: Consumers of assessment metadata MUST NOT treat
results as equivalent to security certifications. A high value
does not guarantee the absence of vulnerabilities. Consumers
SHOULD treat results as one signal among many and SHOULD NOT make
high-stakes trust decisions based solely on RDAP assessment
fields.
Staleness: Results reflect the state at the time indicated by
"scoreDate". Consumers SHOULD check freshness and SHOULD treat
results that have not been updated recently, or that are past
their "validUntil", with appropriate skepticism.
Evidence URI: The resource identified by "evidenceUri" is maintained
by the issuer and is outside the control of the RDAP server. Its
content may change over time, may be subject to access control,
and may become unavailable. Consumers SHOULD NOT assume that the
evidence resource is publicly accessible or immutable.
11.1. Provenance and Authenticity
Three distinct properties are frequently conflated when reasoning
about assessment metadata, and this document separates them
explicitly.
Identity: To whom a result is attributed. The "scoreIssuer" member
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conveys this, and the requirement that it be a stable globally
unique URI ensures that the attribution is unambiguous.
Trust: Whether the consumer has grounds to rely on the named issuer.
This is established out of band and is not conveyed by the
protocol.
Authenticity: Whether the assertion in fact originated with the
named issuer and was relayed unaltered. This is not established
by the protocol.
The "scoreIssuer" member records to whom a result is attributed. It
does not demonstrate that the named issuer produced it, nor that the
publishing server relayed it unaltered.
Where the assessor operates its own assessment service, trust in the
endpoint and trust in the issuer can reasonably coincide, because the
consumer's out of band trust configuration names both. Where a
registry, registrar, or other server republishes an assessor's
result, the consumer must additionally trust the publisher as an
intermediary, and this document provides no means by which a consumer
can distinguish the two cases from the response alone.
This is a known limitation of the present revision, stated here
rather than left implicit. Consumers SHOULD establish out of band
trust in both the issuer and the publishing server before acting on
assessment data. The definition of a signed assessment assertion,
which would permit authenticity to be established in band and would
allow republication without additional trust in the intermediary, is
left to future work. Whether it could be expressed as an addition
within this extension or would need a separate one would depend on
its design.
12. Privacy Considerations
The fields defined in this extension describe security posture at the
registrar and domain level and are not intended to expose personal
data. They are designed to be compatible with the access control
framework defined in [RFC7481].
Implementers SHOULD assess whether the presence or absence of
assessment metadata can reveal information about the identity of
natural persons, and SHOULD withhold publication or coarsen its
granularity where it can. The separation between assessment
metadata, which is designed to be accessible where server policy and
applicable access controls permit, and contact data, which server
policy commonly places behind access control, is to be maintained in
conformant implementations.
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Assessment results published in respect of domain objects warrant
particular care. A domain may be registered by a natural person, and
a result describing the security posture of that domain may in some
circumstances permit inferences about that person, independently of
whether contact data is disclosed. The requirement in Section 8 that
a scheme justify domain-level publication specifically is intended in
part to address this.
This extension is intended to be compatible with applicable data
protection regulations, including the General Data Protection
Regulation [GDPR] and equivalent frameworks.
The "evidenceUri" field, if populated, SHOULD NOT point to resources
that expose personal data or operationally sensitive details beyond
what is necessary for the consumer to understand the result.
13. IANA Considerations
13.1. RDAP Extensions Registry
This document requests the registration of the following entry in the
RDAP Extensions Registry, using the template defined in Section 8.1
of [RFC7480]:
Extension identifier: reliabilityAssessment
Registry operator: Any
Published specification: [BCSEC-RDAP-RA], pending publication of
this document as an RFC
Person & email address to contact for further information: Bertoldi
Cybersecurity alessandro@bertoldicybersecurity.com
(mailto:alessandro@bertoldicybersecurity.com)
Intended usage: COMMON
Registration in this registry is subject to a Specification Required
policy. Section 7.1.2 of [I-D.ietf-regext-rdap-extensions]
additionally requires that an extension be documented in a stable,
non-changing, and readily available reference that is not denoted as
a work in progress. An Internet-Draft does not satisfy that
requirement.
The authors have accordingly published a stable specification of this
extension at [BCSEC-RDAP-RA], and the registration above is requested
against that reference. That document is technically aligned with
this one. It carries no normative reference to a work in progress,
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it requests no registration in the RDAP JSON Values Registry, and it
omits passages that solicit review; the differences are listed in
full in an appendix to that document. Should this document be
published as an RFC, the authors will request that the registry entry
be updated to reference the RFC in place of it.
The -02 revision of this document stated that registration was
expected to occur only upon publication as an RFC, and that nothing
in it should be read as reserving the identifier in the interim.
That statement is superseded. The constraint it reflected was the
absence of a stable reference, and that absence has been remedied
rather than waived. Publication of a separate specification asserts
no consensus of any kind, and nothing in it or in this document is
intended to preclude any decision this Working Group may take
concerning this work, including a decision not to adopt it.
13.2. RDAP JSON Values Registry
This document requests the registration of a new value type in the
RDAP JSON Values Registry, in accordance with Section 7.2 of
[I-D.ietf-regext-rdap-extensions].
Type: assessment status
JSON field: the "status" member of an assessment result object, as
defined in Section 7.6
The following values are requested for that type: "active", "under
review", "withdrawn". Each is to be registered with this document as
its published specification.
14. References
14.1. Normative References
[I-D.ietf-regext-rdap-extensions]
Newton, A., Singh, J., and T. Harrison, "RDAP Extensions",
Work in Progress, Internet-Draft, draft-ietf-regext-rdap-
extensions-15, 13 August 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-regext-
rdap-extensions-15>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
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[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/rfc/rfc3339>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/rfc/rfc3986>.
[RFC7480] Newton, A., Ellacott, B., and N. Kong, "HTTP Usage in the
Registration Data Access Protocol (RDAP)", STD 95,
RFC 7480, DOI 10.17487/RFC7480, March 2015,
<https://www.rfc-editor.org/rfc/rfc7480>.
[RFC7481] Hollenbeck, S. and N. Kong, "Security Services for the
Registration Data Access Protocol (RDAP)", STD 95,
RFC 7481, DOI 10.17487/RFC7481, March 2015,
<https://www.rfc-editor.org/rfc/rfc7481>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC9082] Hollenbeck, S. and A. Newton, "Registration Data Access
Protocol (RDAP) Query Format", STD 95, RFC 9082,
DOI 10.17487/RFC9082, June 2021,
<https://www.rfc-editor.org/rfc/rfc9082>.
[RFC9083] Hollenbeck, S. and A. Newton, "JSON Responses for the
Registration Data Access Protocol (RDAP)", STD 95,
RFC 9083, DOI 10.17487/RFC9083, June 2021,
<https://www.rfc-editor.org/rfc/rfc9083>.
[RFC9224] Blanchet, M., "Finding the Authoritative Registration Data
Access Protocol (RDAP) Service", STD 95, RFC 9224,
DOI 10.17487/RFC9224, March 2022,
<https://www.rfc-editor.org/rfc/rfc9224>.
14.2. Informative References
[BCSEC-RDAP-RA]
Bertoldi, A., "RDAP Extension for Structured Reliability
Assessment Metadata, Specification bcsec-RDAP-RA, Version
1", September 2026, <https://bcsec.io/rdap/v1/bcsec-rdap-
reliability-assessment.txt>.
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[DEEPSEC2025]
Bertoldi, A. and S. P. Romano, "Forever-Day at Scale:
Hijacking Registrars, Defeating 2FA and Spoofing 17,000+
Domains (Even with DMARC p=reject)", DeepSec Vienna 2025,
2025,
<https://bcsec.io/research/deepsec2025/deepsec2025.pdf>.
[GDPR] European Parliament and Council of the European Union,
"Regulation (EU) 2016/679 of the European Parliament and
of the Council on the protection of natural persons with
regard to the processing of personal data and on the free
movement of such data, and repealing Directive 95/46/EC
(General Data Protection Regulation)", April 2016,
<https://eur-lex.europa.eu/legal-content/EN/
TXT/?uri=CELEX:32016R0679>.
[I-D.ietf-regext-rdap-versioning]
Gould, J., Keathley, D., and M. Loffredo, "Versioning in
the Registration Data Access Protocol (RDAP)", Work in
Progress, Internet-Draft, draft-ietf-regext-rdap-
versioning-07, 31 July 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-regext-
rdap-versioning-07>.
[I-D.loffredo-regext-rdap-verified-contacts]
Loffredo, M., Martinelli, M., Gould, J., and P. Kowalik,
"Registration Data Access Protocol (RDAP) Extension for
Verified Contact Information", Work in Progress, Internet-
Draft, draft-loffredo-regext-rdap-verified-contacts-04, 24
August 2026, <https://datatracker.ietf.org/doc/html/draft-
loffredo-regext-rdap-verified-contacts-04>.
[ISO27001] ISO/IEC, "Information security, cybersecurity and privacy
protection -- Information security management systems --
Requirements", ISO/IEC 27001:2022, 2022.
[ISO27701] ISO/IEC, "Information security, cybersecurity and privacy
protection -- Privacy information management systems --
Requirements and guidance", ISO/IEC 27701:2025, 2025.
[NIS2] European Parliament and Council of the European Union,
"Directive (EU) 2022/2555 of the European Parliament and
of the Council on measures for a high common level of
cybersecurity across the Union", December 2022,
<https://eur-lex.europa.eu/legal-content/EN/
TXT/?uri=CELEX:32022L2555>.
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[PIR-AIP] Public Interest Registry, "PIR Abuse Intervention Program
and Quality Performance Index", 2025,
<https://icann85.sched.com/event/2GwoE/ssac-work-session-
pir-abuse-intervention-program>.
[PIR-QPI] Public Interest Registry, "Quality Performance Index",
<https://pir.org/our-impact/qpi/>.
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements",
RFC 4033, DOI 10.17487/RFC4033, March 2005,
<https://www.rfc-editor.org/rfc/rfc4033>.
[RFC6376] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed.,
"DomainKeys Identified Mail (DKIM) Signatures", STD 76,
RFC 6376, DOI 10.17487/RFC6376, September 2011,
<https://www.rfc-editor.org/rfc/rfc6376>.
[RFC7208] Kitterman, S., "Sender Policy Framework (SPF) for
Authorizing Use of Domains in Email, Version 1", RFC 7208,
DOI 10.17487/RFC7208, April 2014,
<https://www.rfc-editor.org/rfc/rfc7208>.
[RFC8521] Hollenbeck, S. and A. Newton, "Registration Data Access
Protocol (RDAP) Object Tagging", BCP 221, RFC 8521,
DOI 10.17487/RFC8521, November 2018,
<https://www.rfc-editor.org/rfc/rfc8521>.
[RFC9989] Herr, T., Ed. and J. Levine, Ed., "Domain-Based Message
Authentication, Reporting, and Conformance (DMARC)",
RFC 9989, DOI 10.17487/RFC9989, May 2026,
<https://www.rfc-editor.org/rfc/rfc9989>.
Appendix A. Changes from -02
This appendix summarizes the changes made in this revision. It is
intended to be removed prior to publication. No change in this
revision affects the data model, the extension identifier, the JSON
member name, or the wire format.
A.1. Registration
* Section 13 has been rewritten. The -02 stated that registration
in the RDAP Extensions Registry was expected to occur only upon
publication of this document as an RFC, and that nothing in it
should be read as reserving the identifier in the interim. A
stable specification has since been published at [BCSEC-RDAP-RA],
the registration is requested against that reference, and the
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earlier statement is superseded. The reasoning is given in
Section 13 rather than only here.
* The "Published specification" field of the registration template
now names [BCSEC-RDAP-RA] in place of "this document".
A.2. Corrections
* The description of PIR's Quality Performance Index has been
corrected in Appendix D and in the section on the PIR Abuse
Intervention Program. The -02 described QPI as operating "within
a single registry context" and as focused on abuse outcomes and
operational metrics in contrast to structural indicators. Both
characterisations were wrong. PIR names SSL and DNSSEC among its
three secondary indicators, and those are structural, and PIR
states that it has made the program and its algorithm available to
all members of the domain industry. The error was acknowledged to
PIR before this revision was submitted.
* The -02 changelog omitted a change that the -02 in fact made: the
DMARC reference was updated from RFC 7489 to [RFC9989]. It is
recorded here.
* A reference to [PIR-QPI] has been added, so that the description
of the program cites the program's own documentation rather than
only a conference session.
A.3. Technical corrections
* The description of the bootstrap mechanism in Section 5 has been
corrected. The -02 stated that [RFC9224] determines the
authoritative server for registration data without qualification.
Section 9 of that document lists entities among the objects it
does not bootstrap, and Section 6 points to [RFC8521] for them.
The scope is now stated.
* The definitions of "scoreValue" and "scoreMaxValue" contradicted
each other. The -02 described "scoreMaxValue" as the maximum
possible value while permitting a scheme to define a "scoreValue"
exceeding it. "scoreMaxValue" is now the upper bound of the range
defined by the scheme, and "scoreValue" MUST NOT exceed it.
* "scoreScheme" no longer has an undefined non-URI form. A URI is
now RECOMMENDED, and a value that is not a URI is stated to be
opaque and meaningful only relative to its issuer. A rule for
comparing "scoreScheme" and "scoreIssuer" has been added, since
those two members together key the uniqueness requirements of this
document.
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* Normative requirements addressed to a document, a response, or an
act of interpretation have been re-addressed to clients, which are
the parties able to satisfy them. The requirement in the Privacy
Considerations that implementers ensure no inference about natural
persons is possible has been reduced to a SHOULD, since the same
section acknowledges that such inferences may occur.
* The minimal response in Section 5 now states that it does not
displace the recommendation in [RFC9083] that a server provide a
link identifying the object class instance itself.
* ISO/IEC 27001 and ISO/IEC 27701 are described as standards against
which a party is certified, rather than as certifications.
* The Abuse Intervention Program is no longer described as being in
operation, since the authors have not verified that from a primary
source.
A.4. Changes from -01, retained for continuity
The remainder of this appendix records the changes made in the -02
revision.
A.5. Breaking Changes
* The extension identifier has been changed from
"reliabilityScoring" to "reliabilityAssessment", aligning it with
the title of the document and avoiding the reading of the
extension as a rating mechanism. The document name is unchanged
in order to preserve continuity in the datatracker.
* The JSON member has been renamed from
"reliabilityScoring_assessment" to "reliabilityAssessment_results"
and now carries an array of result objects rather than a single
object. Results from more than one issuer or scheme on the same
object are a natural case, and moving from object to array in a
later revision would itself have been a breaking change.
* "scoreScheme" and "scoreIssuer" are now REQUIRED in each result
object.
* "scoreIssuer" MUST now be a URI. It was previously an opaque
string whose format was defined by the scheme.
These changes are made together in a single revision, and at a point
at which the authors are aware of no implementations.
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A.6. Additions
* Section 5, describing deployment configurations, minimal response,
endpoint discovery, and the rejected referral mechanism.
* Section 6, describing binding for domains and registrars and
stating the open questions concerning [RFC8521] and registrars
without an IANA Registrar ID.
* Section 8, placing requirements on the specification of any scheme
whose results are intended for publication through RDAP, including
notification, a remediation and contestation period, and a
disclosure threat model.
* Section 11.1, separating identity, trust, and authenticity, and
stating the limitations of the present revision.
* The "validUntil", "assessmentId", and "status" members, and
Section 7.6 defining permitted status values.
* Section 10, stating that no implementations are known.
* An "Extension Version Identifier" section declaring Opaque
Versioning, following the guidance in Section 6.1 of
[I-D.ietf-regext-rdap-versioning]. The -01 was silent on
versioning.
* Sections on scheme stability and on the absence of the member, the
latter promoted from an appendix in -01 and expanded.
* Expanded Security Considerations covering reconnaissance and
exposure, risk-based regulatory obligations, perception as a
rating, volatility, access control and server policy, and
inference from absence.
* A registration request for the RDAP JSON Values Registry.
A.7. Corrections
* The IANA Considerations section now uses the complete template
from Section 8.1 of [RFC7480], including the "Intended usage"
field omitted in -01.
* Section references to [I-D.ietf-regext-rdap-extensions] have been
updated to the numbering of the -15 revision.
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* [I-D.ietf-regext-rdap-extensions] has been moved from an
informative to a normative reference. This document depends on it
for identifier syntax, for the treatment of child JSON values, and
for the procedures governing registration of a new value type, and
cannot be implemented conformantly without it.
* The reference to ISO/IEC 27701 has been corrected to the 2025
edition, which carries a revised title.
A.8. Deferred
The authors considered and did not include a representation of
confidence or uncertainty, a representation of categorical rather
than numeric outcomes, and a supersession mechanism. In each case no
requirement from an implementer or prospective consumer has been
identified. The restructuring of the member into an array of result
objects means that each could be added later as an additional member
without a breaking change.
Appendix B. Acknowledgments
The authors thank Gavin Brown, James Galvin, James Gould, Jody
Kolker, Pawel Kowalik, Mario Loffredo, Maurizio Martinelli, Jim Reid,
Werner Staub, Richard Wilhelm, and Maarten Wullink.
The deployment model in Section 5, the treatment of contestation, and
the expanded disclosure considerations are responses to points raised
in the REGEXT session at IETF 126 and in subsequent discussion on the
mailing list.
Appendix C. Example RDAP Responses
The examples in this appendix are provided for illustrative purposes
only. Values, scheme identifiers, and issuer identifiers are
fictional.
C.1. Domain Lookup with a Single Result
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{
"rdapConformance": [
"rdap_level_0",
"reliabilityAssessment"
],
"objectClassName": "domain",
"handle": "D-EXAMPLE-1",
"ldhName": "example.com",
"reliabilityAssessment_results": [
{
"scoreScheme": "https://assessor.example/schemes/domain/v2",
"scoreIssuer": "https://assessor.example",
"scoreValue": 9,
"scoreMaxValue": 10,
"scoreDate": "2026-01-01T00:00:00Z",
"validUntil": "2026-04-01T00:00:00Z",
"assessmentId": "d-2026-01-01-7781",
"status": "active",
"evidenceUri": "https://assessor.example/rep/d-2026-01-01-7781"
}
],
"events": [
{
"eventAction": "registration",
"eventDate": "2024-01-01T00:00:00Z"
}
]
}
C.2. Registrar Lookup with Results from Two Issuers
This example illustrates the case for which the array representation
is defined: two issuers, applying different schemes, have published
results in respect of the same registrar. The second result is under
review following a contestation by the assessed party.
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{
"rdapConformance": [
"rdap_level_0",
"reliabilityAssessment"
],
"objectClassName": "entity",
"handle": "REGISTRAR-EXAMPLE",
"roles": ["registrar"],
"publicIds": [
{
"type": "IANA Registrar ID",
"identifier": "999999"
}
],
"reliabilityAssessment_results": [
{
"scoreScheme": "https://assessor.example/schemes/registrar/v1",
"scoreIssuer": "https://assessor.example",
"scoreValue": 10,
"scoreMaxValue": 10,
"scoreDate": "2026-01-01T00:00:00Z",
"assessmentId": "r-2026-01-01-0003",
"status": "active"
},
{
"scoreScheme": "https://observatory.example/scheme/2026",
"scoreIssuer": "https://observatory.example",
"scoreValue": 62,
"scoreMaxValue": 100,
"scoreDate": "2026-02-10T00:00:00Z",
"assessmentId": "2026-02-10-REG-9999",
"status": "under review"
}
]
}
C.3. Domain Lookup without Assessment Metadata
When no assessment metadata is conveyed, the
"reliabilityAssessment_results" member is omitted. Its absence MUST
NOT be interpreted as evidence that the object has not been assessed,
nor as a negative assessment. See Section 7.8.
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{
"rdapConformance": [
"rdap_level_0"
],
"objectClassName": "domain",
"handle": "D-PLAIN-1",
"ldhName": "plain.example",
"events": [
{
"eventAction": "registration",
"eventDate": "2025-06-01T00:00:00Z"
}
]
}
Appendix D. Illustrative Assessment Dimensions
This appendix describes possible dimensions that an operational
assessment program might evaluate when producing results to be
carried by the envelope defined in this document. This content is
entirely non-normative. Nothing in this appendix constrains
implementers or defines mandatory evaluation criteria, and nothing in
it should be read as a recommendation that any of these dimensions be
published in the form described.
The intent is to demonstrate that the envelope model is expressive
enough to carry results from real-world assessment programs,
including those derived from existing empirical research on registrar
security posture [DEEPSEC2025].
D.1. Possible Registrar Assessment Dimensions
An operational program might evaluate registrars across dimensions
such as: the strength of customer identity verification procedures;
the adoption and enforcement of multi-factor authentication for
customer-facing and internal systems; the possession of recognized
information security certifications such as ISO/IEC 27001 [ISO27001]
or ISO/IEC 27701 [ISO27701]; the correctness of email authentication
configurations including SPF [RFC7208], DKIM [RFC6376], and DMARC
[RFC9989] on registrar-operated domains; the existence of documented
security policies; and the regularity of cybersecurity training
programs for staff.
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D.2. Possible Domain Assessment Dimensions
An operational program might evaluate individual domains across
dimensions such as: the strength of owner identity verification at
registration or renewal; the level of TLS certificate validation
used; the correctness of SPF, DKIM, and DMARC configurations; the
implementation of DNSSEC [RFC4033]; and the absence of the domain
from monitored abuse blocklists over a defined observation period.
The considerations in Section 11 apply with particular force to
dimensions of this kind, since several of them describe exploitable
weaknesses directly.
D.3. Note on Existing Operational Programs
Existing programs differ in what they measure. PIR's Quality
Performance Index [PIR-QPI] combines observable abuse and commercial
outcomes, being Abuse Takedown, Renewal Rates, and Domain Usage, with
secondary indicators named by PIR as SSL, DNSSEC, and ATL, of which
the first two are structural. The dimensions described above in this
appendix are weighted more heavily toward structural and procedural
security posture, including identity verification and credential
recovery practice, which the published description of QPI does not
list among its indicators.
The two are neither equivalent nor mutually exclusive, and the
envelope defined in this document is agnostic to the methodology. It
can carry results from either, and from both at once, since the
envelope is an array keyed by the combination of scheme and issuer.
Authors' Addresses
Alessandro Bertoldi
Bertoldi Cybersecurity
Italy
Email: alessandro@bertoldicybersecurity.com
Simon Pietro Romano
Universita' degli Studi di Napoli Federico II
Via Claudio 21
80125 Naples
Italy
Email: spromano@unina.it
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