A Brief Note on Cryptographic Pseudonyms for Anonymous Credentials

Abstract: This paper describes pseudonyms for the upcoming European Identity Wallet (EUDIW) architecture from both a cryptographic and an implementation perspective. Its main goal is to provide technical insights into the achievable properties and cryptographic realizations. In particular, we (1) outline the security and privacy requirements of EUDI pseudonyms as the basis for building consensus on the cross-country decision maker level; (2) sketch an abstract cryptographic protocol that fulfills these requirements; and (3) suggest two instantiation options for the protocol sketch based on well-studied building A complete specification of the formal properties, as well as the specific set of credential issuance, provisioning, and pseudonym presentation generation is outside the scope of this paper, but is expected to follow as future work.