A method for processing biometric data performed by a proof entity and a verification entity; the proof entity having a biometric candidate datum, a biometric reference datum, a hash value of the biometric reference datum, a hash value of the biometric candidate datum; the verification entity having only the hash value of the biometric candidate datum; the method including steps of: generation by a data-processing unit of the proof entity of a zero-knowledge proof of the assumption that the biometric candidate datum and the biometric reference datum coincide; transmission to the verification entity of said zero-knowledge proof, the hash value of the biometric candidate datum, and the hash value of the biometric reference datum; verification by a data-processing unit of the verification entity that the zero-knowledge proof is valid, and that the hash value received from the biometric candidate datum corresponds to the one the verification entity has.