(title available in French only)
Official Binding
Note
IETF specification defining the Concise Binary Object Representation (CBOR), a data format aiming at very small code and messages, which replaces RFC 7049.
The full text is not reproduced here (copyright): see the official source.
Summary
Purpose
IETF RFC 8949 (December 2020) defines CBOR (Concise Binary Object Representation), a binary data representation format:
The Concise Binary Object Representation (CBOR) is a data format whose design goals include the possibility of extremely small code size, fairly small message size, and extensibility without the need for version negotiation.
It obsoletes RFC 7049, without creating a new version of the format RFC 8949, [Abstract](#abstract). The “mdoc” data model of standard ISO/IEC 18013-5, used for PID and attestations, encodes its elements in CBOR § 3. Parties utiles pour eIDAS 2.
Who it applies to
The RFC itself imposes nothing under eIDAS. It applies by reference to providers of person identification data (PID), who ensure that the PID issued comply with the annex to Implementing Regulation 2024/2977 Art. 3(3).
The reference concerns the encoding of PID in the ISO/IEC-mdoc format (section 4.1 of the annex), and only section 4.2 of the RFC Annex.
Key points
- Integers as small as possible. Integers of major types 0 and 1 (unsigned integers and negative integers RFC 8949, [3.1.](#section-3.1) [Major Types](#name-major-types)) must be as small as possible, as specified in section 4.2 of the RFC Annex.
- Lengths as short as possible. The expression of the length of a byte string (
bstr), a text string (tstr), an array or a map must be as short as possible, as specified in the same section Annex. - What section 4.2 says. It defines restrictions that can serve as the basis for a “deterministic” encoding RFC 8949, [4.2.](#section-4.2) [Deterministically Encoded CBOR](#name-deterministically-encoded-c). Its core requirements include that integers and lengths be encoded in as few bytes as possible RFC 8949, [4.2.1.](#section-4.2.1) [Core Deterministic Encoding Requirements](#name-core-deterministic-encoding).
- What the act does not expressly take up. Section 4.2.1 also contains other restrictions: no indefinite-length items, keys in every map sorted in a defined order RFC 8949, [4.2.1.](#section-4.2.1) [Core Deterministic Encoding Requirements](#name-core-deterministic-encoding). The annex cites section 4.2 only for integers and lengths Annex.
- The types used. The
tstr,bstranduinttypes in Table 6 of the annex are written in CDDL, the notation of RFC 8610 Annex.
Clauses referred to by the act
- Section 4.2 (deterministic encoding), for two rules: minimal integers, minimal lengths Annex.
- The rest of the RFC is not cited by the annex.
- The annex to Implementing Regulation 2024/2977 was replaced by Implementing Regulation 2026/1731 Implementing Regulation (EU) 2026/1731; this summary cites the consolidated version that incorporates it.
Links
- Act that makes it applicable: Implementing Regulation 2024/2977 Implementing Regulation (EU) 2024/2977 — consolidated version of 11/08/2026.
- Related standards: RFC 8610, CDDL notation RFC 8610; RFC 8943, CBOR tags for date RFC 8943; RFC 9360, COSE headers RFC 9360; ISO/IEC 18013-5 ISO/IEC 18013-5:2021.
- Learning path: step 3, the European wallet.
Consolidation without official value
This summary relies on the consolidated version of Implementing Regulation 2024/2977 published on EUR-Lex Implementing Regulation (EU) 2024/2977 — consolidated version of 11/08/2026. It serves as documentation: only the text published in the Official Journal is authentic.
Written by Asphalia.