Date and Time on the Internet: Timestamps

Note

IETF specification defining, for Internet protocols, a date and time format that is a profile of ISO 8601, in the Gregorian calendar.

Summary

Purpose

IETF RFC 3339 (July 2002) defines a date and time format for Internet protocols:

It targets a specific use: time-stamping events in Internet protocols. Every time is expressed with its offset from Coordinated Universal Time (UTC) RFC 3339, § 1. Introduction.

Who it applies to

The RFC itself imposes nothing under eIDAS. It applies by reference:

• to providers of person identification data (PID, the data that identify the user in their wallet), who ensure that the PID issued comply with the technical specifications in the annex to Implementing Regulation 2024/2977 Art. 3(3);
• more precisely, to the encoding of PID in the ISO/IEC-mdoc format, described in section 4.1 of that annex Annex. This “mdoc” format comes from standard ISO/IEC 18013-5 on the mobile driving licence § 3. Parties utiles pour eIDAS 2.

Key points

• Two types of date. In the mdoc encoding of PID, the tdate attribute must contain a date-time string specified in RFC 3339; the full-date attribute must contain a full-date string specified in RFC 3339, in accordance with RFC 8943 Annex.
• Choices narrowed by the act. Unless otherwise specified, a date in the attributes must not use fractions of seconds or a local offset from UTC; the offset provided for by the RFC must be set to “Z” Annex.
• The dates concerned. Table 6 of the annex encodes the date of birth (birth_date) as full-date, and the expiry date (expiry_date) and the issuance date (issuance_date) as tdate or full-date Annex.
• The grammar of the RFC. A full date (full-date) is written year-month-day; a date-time (date-time) joins the date and the time with the letter “T”; the offset is written “Z” or in numeric form RFC 3339, § 5.6. Internet Date/Time Format.
• Value limits. The hour only runs from 00 to 23; the second may be 60 during a leap second RFC 3339, § 5.7. Restrictions.
• The unknown offset. The RFC provides the notation “-00:00” when the time in UTC is known but the local offset is not; it differs from “Z” RFC 3339, § 4.3. Unknown Local Offset Convention. Unless otherwise specified, the act requires “Z” Annex.

Clauses referred to by the act

• The annex to Implementing Regulation 2024/2977 refers to the RFC as a whole, without a clause number, for the date-time string and the full-date string Annex.
• Adaptation imposed: no fractions of seconds, no local offset, offset set to “Z”, unless otherwise specified 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 8943, CBOR tags for date RFC 8943; ISO 8601, of which the RFC is a profile ISO 8601-1 RFC 3339, Abstract.
• Learning path: step 3, the European wallet.

Written by Asphalia.