Towards a Privacy-Preserving National Identity Card

In this paper, we propose to replace the national identity card, currently used in many countries, by a personal device that allows its user to prove some binary statements about himself while minimizing personal information leakage. The privacy of the user is protected through the use of anonymous credentials which allows him to prove binary statements about himself to another entity without having to disclose his identity or any unnecessary information. The proposed scheme also prevents the possibility of tracing the user, even if he proves several times the same statement (unlinkability property). A tamper-proof smartcard is used to store the personal information of the user thus protecting his privacy and preventing the risks of forgery at the same time. The user identifies himself to the card via biometrics thus forbidding an unauthorized use in the situation where the card is stolen or lost. Two practical implementations of the privacy-preserving identity card are described and discussed.