A system comprising: a remote device for providing an operator interface for a user to configure and monitor a process; a controller(28, 30) configured to control the process; and a certificate authority (32, 34) configured to issue and to revoke certificates, wherein the controller is configured to use the certificates to mutually authenticate a user to enter into a secure mode of operation of the controller, in which the user is communicatively coupled with the controller, and in which the user is authorized to interact with the controller (28, 30); wherein the controller (28, 30) is configured to receive a request from the user to enter into the secure mode of operation and to validate a user certificate provided by the user; and if the user certificate is not valid, to alert of a first security violation; if the user certificate is valid, to request and validate a CA certificate from the CA; if the CA is not valid, to alert of a second security violation; if the CA certificate is valid, to request a new controller certificate from the CA and then to enter into the secure mode of operation, wherein in the secure mode operation the controller (28, 30) is configured to receive a user request for communication together with the user certificate, to validate the user certificate and, to alert of a security violation, if the user certificate is invalid, and to submit the controller certificate to the remote device, if the user certificate is valid, and wherein the remote device is configured to validate the controller certificate and to alert of a security violation, if the controller certificate is invalid, and to establish a secure connection, if the controller certificate is valid. a remote device for providing an operator interface for a user to configure and monitor a process; a controller(28, 30) configured to control the process; and a certificate authority (32, 34) configured to issue and to revoke certificates, wherein the controller is configured to use the certificates to mutually authenticate a user to enter into a secure mode of operation of the controller, in which the user is communicatively coupled with the controller, and in which the user is authorized to interact with the controller (28, 30); wherein the controller (28, 30) is configured to receive a request from the user to enter into the secure mode of operation and to validate a user certificate provided by the user; and if the user certificate is not valid, to alert of a first security violation; if the user certificate is valid, to request and validate a CA certificate from the CA; if the CA is not valid, to alert of a second security violation; if the CA certificate is valid, to request a new controller certificate from the CA and then to enter into the secure mode of operation, wherein in the secure mode operation the controller (28, 30) is configured to receive a user request for communication together with the user certificate, to validate the user certificate and, to alert of a security violation, if the user certificate is invalid, and to submit the controller certificate to the remote device, if the user certificate is valid, and wherein the remote device is configured to validate the controller certificate and to alert of a security violation, if the controller certificate is invalid, and to establish a secure connection, if the controller certificate is valid.