1. A method of generating a biometric certificate of a user performed by a data processing device of a certifying authority, comprising: acquiring biometric data of said user; generating a proof of knowledge of said acquired biometric data from the acquired biometric data and a pseudo-random function; generating a truncated authentication datum by applying a truncation function to said generated proof of knowledge; generating a certificate for said user comprising data related to an identity of the user and the truncated authentication datum so that the certificate provides a proof of the user's identity and allows authenticating the user with a reduced rate of error while not allowing identification of the user, wherein said method further comprises, for at least one error to be processed among a determined set of tolerable errors: generating derived biometric data by adding said error to the acquired biometric data, generating derived proofs of knowledge from the generated derived biometric data and from said pseudo-random function, and generating derived truncated authentication data by applying said truncation function to said first generated derived proofs of knowledge.