Method for controlling access to a production system of a computer system not connected to an information system of said computer system

A terminal of a user used for implementing a method for controlling access to a production system of a computer system by a user identified with said production system, said user terminal comprising:

• at least one processor configured to
• enroll the user in the production system by:
• receiving an encrypted private key associated with each account of the user in the production system, and
• transmitting the encrypted private key containing a private key for storing by the information system of said encrypted private key,
• then, during a phase for authentication by the production system, for each request for access to the production system by the user by a station connected to the production system,
• recovering an image encryption code displayed on said station, the image encryption code comprising a piece of encrypted data associated with the account of the user, the piece of encrypted data configured to be decrypted by the associated private key and stored in encrypted form in the information system,
• linking to the information computer system for authentication of the user by said information system,
• receiving the stored encrypted private key for the user account, transmitted by said information system, and
• decrypting the encrypted private key with a secret key to obtain the private key that decrypts the recovered image encryption code and to obtain a password authorizing access to the user account of the production system.

A system for controlling access to the production system that is not connected to the information system of a computer system, the system comprising:

• a terminal of a user used for implementing a method for controlling access to a production system of a computer system by a user identified with the production system, the terminal comprising:
• at least one processor configured to
• enroll the user in the production system by:
• receiving an encrypted private key associated with each account of the user in the production system, and
• transmitting the encrypted private key containing a private key for storing by the information system of said encrypted private key,
• then, during a phase for authentication by the production system, for each request for access to the production system by the user by a station connected to the production system,
• recovering an image encryption code displayed on said station, the image encryption code comprising a piece of encrypted data associated with the account of the user, the piece of encrypted data configured to be decrypted by the associated private key and stored in encrypted form in the information system,
• linking to the information computer system for authentication of the user by said information system,
• receiving the stored encrypted private key for the user account, transmitted by said information system, and
• decrypting the encrypted private key with a secret key to obtain the private key that decrypts the recovered image encryption code and to obtain a password authorizing access to the user account of the production system,
• wherein the production system has, in a memory, identifiers of the user accounts, and the public keys and the private keys associated with each user, the production system being configured to encrypt one of the private keys the associated public key and to generate an image encryption code comprising said private key, and
• wherein the information system has a server that has an authentication base or is connected to an authentication server.