Access key for a field device

A method for providing an access key for a field device of automation technology, comprising:

• producing an individual key;
• storing the individual key in a database together with an identification feature of the field device;
• storing the individual key in the field device, which is to be unlocked based on an input of the access key;
• ascertaining the identification feature of the field device for which the access key is to be provided;
• and
• generating the access key such that it includes at least one hash value, wherein the hash value is formed at least from the individual key read-out from the database using the ascertained identification feature, and wherein the access key controls accessing the field device including the field device's parameters.

A method for unlocking a field device of automation technology using an access key, comprising:

• inputting an access key which includes at least one hash value, wherein the access key controls accessing the field device including the field device's parameters;
• calculating a comparison hash value based on an individual key stored in the field device;
• comparing the comparison hash value with the access key hash value;
• and
• enabling or performing at least one function of the field device when the comparison hash value agrees with the access key hash value.

A field device of automation technology, comprising:

• an internal memory in which an individual key is stored, wherein the internal memory is externally inaccessible;
• and
• a computing unit configured to
• receive an access key including at least one hash value,
• control access to the field device based upon the access key,
• calculate a comparison hash value based on the individual key,
• compare the hash value of the access key with the comparison hash value, and
• enable or perform at least one function of the field device when the comparison hash value agrees with the hash value of the input access key.

A system of automation technology, comprising:

• a plurality of field devices, each field device including an internal memory in which an individual key is stored and a computing unit configured to
• receive an access key including at least one hash value,
• control access to the field device based upon an access key,
• calculate a comparison hash value based on the individual key,
• compare the hash value of the access key with the comparison hash value, and
• enable or perform at least one function of the field device when the comparison hash value agrees with the hash value of the input access key;
• a database of a field device manufacturer, in which the individual keys are stored together with, in each case, an identification feature of the field device;
• and
• an access key generating unit configured to provide an access key for field devices of automation technology, wherein the access key generating unit is configured to generate an access key for a field device, wherein the access key includes a hash value formed at least from the field device's individual key and the field device's identification feature, an offset value, and a bitmask or a representative for the bitmask.