# US 11,870,771 B2 · Method for secure communication between a field device of automation technology and an end device as well as a system for secure communication between a field device and an end device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,870,771 B2 - Document ID: US11870771B2 - Status: Granted - Kind: B2 - Application number: 16/813,195 - Filed: 2020-03-09 - Published: 2020-09-10 - Granted: 2024-01-09 - Earliest claimed: 2019-03-08 - Applicants: KROHNE Messtechnik GmbH - Inventors: Wolfgang Hottgenroth - Web page: https://patentgrep.com/patent/US11870771B2 ## CPC - G05B 19/042: using digital processors (G05B19/05 takes precedence) - H04L 63/0853: {using an additional device, e.g. smartcard, SIM or a different communication terminal (cryptographic mechanisms or cryptographic arrangements for entity authentication involving additional secure or trusted devices H04L9/3234)} - H04L 63/0428: {wherein the data content is protected, e.g. by encrypting or encapsulating the payload} - H04L 63/083: {using passwords (cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226)} - H04L 63/105: {Multiple levels of security} - G05B 2219/24163: Authentication tag in configuration file - G05B 2219/24167: Encryption, password, user access privileges - G05B 2219/25428: Field device - G05B 2219/31131: Field device with gateway functions for communication with pc and other field devices - Y02P 90/02: Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS] - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A method for secure communication between a field device and an end device is disclosed. The method includes: storing an individual access code in the end device, transmitting an access code of the end device to the field device, connecting the field device to an authentication server via a server communication link, using the field device to transmit the access code or an access code derived from the access code to the authentication server, storing authentication data on the authentication server, checking the authenticity of the access code on the authentication server using the authentication data, transmitting the resulting authentication result from the authentication server via the server communication link to the field device, and, depending on the authentication result transmitted to the field device, making resources of the field device available to the end device. ## Claims ### Claim 1 A method for secure communication between a field device in automation technology and an end device connected to the field device via an end device communication link, wherein the field device has a cause-effect relationship with a physical process by measuring a process variable of the physical process by a sensor of the field device, and wherein the field device is connectable via a field bus interface to other field devices and/or a process control system for the exchange of process information, the method comprising: storing an individual access code in the end device; transmitting the access code from the end device to the field device; connecting the field device to an authentication server via a server communication link; using the field device to transmit the access code or an access code derived from the access code to the authentication server; storing authentication data on the authentication server, on the basis of which the authenticity of the access code is checked on the authentication server; transmitting the resulting authentication result from the authentication server via the server communication link to the field device; and depending on the authentication result transmitted to the field device, making resources of the field device available to the end device; wherein the field device at least partially logs the communication with the end device in a transcript for tracing influences on the field device; and wherein the transcript is transmitted to the authentication server upon completion of the communication and the transcript is stored on the authentication server, or is continuously transmitted to the authentication server during communication and the transcript is stored on the authentication server. ### Claim 2 (depends on 1) The method according to claim 1, wherein an individual end device name and an individual end device password are stored as an individual access code; and/or wherein the individual access code has an individual username and an individual user password of a user of the end device connected to the field device. ### Claim 3 (depends on 1) The method according to claim 1, wherein the address of the authentication server is stored in the field device and the server communication link is established using the address of the authentication server. ### Claim 4 (depends on 1) The method according to claim 1, wherein cryptographic means are stored in the field device and in the authentication server, which means allow the field device and the authentication server to exchange encrypted data with one another; wherein the field device with its cryptographic means derives an encrypted derived access code from the access code and transmits it to the authentication server; and wherein the authentication server with its cryptographic means decrypts the encrypted derived access code to the access code. ### Claim 5 (depends on 1) The method according to claim 1, wherein the authentication data of the authentication server also includes scopes of rights associated with an access code; and wherein the authentication result transmitted by the authentication server to the field device also includes the scopes of rights associated with an access code. ### Claim 6 (depends on 5) The method according to claim 5, wherein a scope of rights is one of the following scope of rights: read access only, restricted read access, write access, restricted write access, function request; and wherein the scope of rights is provided with a parameter list and/or function list. ### Claim 7 (depends on 5) The method according to claim 5, wherein the scopes of rights designate groups of sub-rights; wherein the definitions of the groups of sub-rights are either stored on the field device or stored on the authentication server and are transmitted to the field device upon request; and wherein possible groups of sub-rights are user, operator, expert, service, factory. ### Claim 8 (depends on 1) The method according to claim 1, wherein the authentication data of the authentication server also includes session attributes associated with an access code; wherein the authentication result transmitted from the authentication server to the field device also includes the session attributes associated with an access code; and wherein a session attribute includes at least one of: session language, session duration, absolute session time, number of session accesses, session interface. ### Claim 9 (depends on 5) The method according to claim 5, wherein the field device provides the end device with an individualized user interface and the user interface is individualized on the basis of the scopes of rights and/or the session attributes; and wherein the field device provides the end device with the individualized user interface by means of an individualized web server or the field device individualizes the user interface of a physical display of the field device itself. ### Claim 10 (depends on 1) The method according to claim 1, further comprising: performing an evaluation of the transcript to determine a measure that has been taken via a communication between the field device and the end device over the end device communication link. ### Claim 11 (depends on 1) The method according to claim 1, wherein the end device communication link and/or the server communication link is/are designed according to one of the following technologies: Bluetooth, wireless local area network, infrared, Ethernet. ### Claim 12 A system for secure communication, comprising: a field device of automation technology; and an authentication server; wherein the field device has a cause-effect relationship with a physical process by measuring a process variable of the physical process by a sensor of the field device; wherein the field device is configured to be connected to other field devices and/or a process control system; wherein the field device includes data processing electronics, wherein the field device is configured to be connected to an end device via an end device communication interface different from the field bus interface; wherein the field device is connected to the authentication server via a server communication interface; wherein the data processing electronics is designed to receive an individual access code of the connected end device via the end communication interface; wherein the data processing electronics is designed to transmit the access code or an access code derived from the access code to the authentication server via the server communication interface; wherein authentication data is stored on the authentication server, on the basis of which the authenticity of the access code is checked on the authentication server; wherein the data processing electronics is designed to receive an authentication result determined by the authentication server via the server communication interface; wherein the data processing electronics makes resources of the field device available to the end device depending on the received authentication result; wherein the field device at least partially logs the communication with the end device in a transcript for tracing influences on the field device; and wherein the transcript is transmitted to the authentication server upon completion of the communication and the transcript is stored on the authentication server, or is continuously transmitted to the authentication server during communication and the transcript is stored on the authentication server. ### Claim 13 (depends on 12) The system according to claim 12, wherein the field device and the authentication server are designed to carry out a method including the steps of: storing an individual access code in the end device; transmitting the access code from the end device to the field device; connecting the field device to an authentication server via a server communication link; using the field device to transmit the access code or an access code derived from the access code to the authentication server; storing authentication data on the authentication server, on the basis of which the authenticity of the access code is checked on the authentication server transmitting the resulting authentication result from the authentication server via the server communication link to the field device; and depending on the authentication result transmitted to the field device, making resources of the field device available to the end device. ### Claim 14 (depends on 12) The system according to claim 12, wherein the server communication interface, the end device communication interface and any software services associated with these communication interfaces are implemented on the field device isolated from the field bus interface and from software services associated with the field bus interface, so that an influencing of the field bus interface and of software services associated with the field bus interface via the server communication interface, via the end device communication interface and via any software services associated with these communication interfaces is not possible.