1. A device for protection of data and executable codes of a fixed or portable computer system with a memory medium to be protected, the device comprising: a security and protection device located physically between the computer system and the memory medium to be protected and configured to allow the computer system access to the data and codes to be protected after execution of protection functions; the security and protection device configured to execute the protection functions prior to allowing the computer system access to the data and codes; the security and protection device configured to execute the protection functions independently of a machine code executed by the computer system; and the security and protection device configured to execute the protection functions without requiring interaction with a processor of the system, wherein the device has two operating modes that are independent and not simultaneous, the two operating modes including an administrator mode and a user mode, and wherein authentication of an administrator is effected by the device itself by means of interface resources between the administrator and the device which are invisible to the computer system.