Method for Secure Communication with a Field Measuring Device of Process Measuring Technology and a Corresponding Field Measuring Device of Process Measuring Technology

A method is described for secure communication with a field measuring device of process measuring technology. A plurality of scopes of rights, and a plurality of public keys of a corresponding plurality of asymmetrical key pairs, are stored in the field measuring device. Each public key is assigned a scope of rights, and at least one private key of the corresponding plurality of asymmetric key pairs is stored in an external communicator. Upon establishing contact of the external communicator with the field measuring device, the external communicator identifies itself by a public-key authentication with the stored private key to the field measuring device. The field measuring device authenticates the external communicator using a suitable public key stored in the field measuring device. The field measuring device then opens an operating session in which the external communicator is granted access to the information technology content of the field measuring device.