The invention relates to a system implements a mobile phone (20) available to a user (18) authorized to open a lock (22). A remote management site (10) includes a database (12) of locks and authorized users identified by the mobile phone number thereof, as well as a generator (14) of accreditation data. The accreditations are encrypted acoustic accreditations in the form of single-use audio signals, capable of enabling the opening of locks that are indexed in the database. The system includes means for securely transmitting the encrypted acoustic accreditations from the management site to the mobile phone of the corresponding authorized user via a mobile network operator (16). The lock (22) includes an electroacoustic transducer that is capable of sensing the acoustic accreditations reproduced by the telephone placed beforehand near the lock, as well as a means for recognizing, analyzing, and authenticating the sensed acoustic accreditations, and controlling the unlocking of the mechanical members upon recognizing a compliant accreditation.