How to make the e-ID unlinkable
In its decision of 6 December 2024 (e-ID: Federal Council takes decision on technical implementation), the Federal Council ruled that eID must be unlinkalbe. Unlinkability (What does unlinkability mean?) refers to the impossibility of linking different transactions that are carried out with an e-ID. In other words, it is about the question of whether it is possible to trace what a person does with their e-ID.
In collaboration with the DDPS (Federal Department of Defence, Civil Protection and Sport), the e-ID team has produced the white paper ‘Key Management for e-ID – Batch Issuance and Renewal’. The white paper describes how unlinkability can be implemented using batch issuance, as presented at the participation meeting in May 2025. The white paper explains how cryptographic keys are managed for e-ID issuance and how automatic renewal of the e-ID batch can be implemented.
In its decision, the Federal Council also stipulated that the implementation of unlinkability can only take place in a second phase, after the introduction of e-ID. It is now clear that unlinkability will be implemented as soon as e-ID is introduced (in the third quarter of 2026 at the earliest).