The electronic device, in particular a transponder, includes a non volatile memory (EEPROM) having a plurality of words 1 to N whose read and/or write access can be locked. The protection register (22) is formed of two protection words A and B these two protection words are alternately active and inactive during the successive locking of words 1 to N of the programmable memory (16). The state of the protection register is defined by the active word. An initially active word is not deleted until the content thereof has been copied into the inactive word. Once the content has been altered in accordance with the lock command, the initially inactive word becomes the active word of the protection register.