This document presents the another way to leverage the best of the centralized and decentralized approaches for an exposure notification system, with the goal to have an interoperable protocol in the mid-term at the European level : the DESIRE protocol – a decentralized evolution of the ROBust and privacy-presERving proximity Tracing scheme (ROBERT). There are two major improvements brought DESIRE: 1. While ROBERT relied only on temporary pseudonyms for users’ applications, DESIRE relies on “Private Encounter Tokens” (PETs) that associate a unique and secret pseudonym exclusively during an encounter between two mobile devices that were in proximity to each other. PET tokens are generated jointly and privately by the applications of these two users and are unforgeable, thus providing a high level of privacy protection. This generation local to the applications is a significant form of decentralisation. 2. All the data that is stored by the central authority is now encrypted with the secret keys that are stored on users’ devices, thus providing a strong protection against data breaches. These new features improve drastically the privacy guarantees of DESIRE scheme with respect to the authority or malicious users.