1. A security and protection device ( 1 ) for protection of the data and executable codes of any fixed or portable computer system ( 2 ) with a memory medium (MP) to be protected, said security and protection device ( 1 ) being located physically between the computer system ( 2 ) and the memory medium (MP) to be protected in order to allow the computer system ( 2 ) access to the data and codes to be protected after execution of protection functions independently of a machine code executed by the computer system ( 2 ) and requires no interaction with a processor of the system for the execution of said protective functions.