A system is provided for controlling access to protected data. The system includes storage means, protection means, an internal key, and means for receiving an input key from the outside. The storage means includes a protected zone for storing the protected data, and a command input for denying or authorising access to the protected data. The protection means controls access to the protected data by selectively activating the command input of the memory. The protection means authorises access to the protected data only when the internal key and the input key are identical. Also provided is a method for controlling access to protected data stored in a protected zone of a storage means. According to the method, an input key is received from the outside, and access to the protected data is authorised only when the input key and an internal are identical.