DATA STRUCTURE FOR USE AS A POSITIVE LIST IN A DEVICE, METHOD FOR UPDATING A POSITIVE LIST AND DEVICE

• US 20170288880A1
• Filed: 03/13/2017
• Published: 10/05/2017
• Est. Priority Date: 03/30/2016
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: BROCKHAUS, HENDRIK, FALK, RAINER, SELTZSAM, STEFAN
• Granted Patent: US 10,461,941 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/3263 involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823
• CPC Class Codes: H04L 9/3268 using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]

Abstract

A data structure is provided for use as a positive list in a device, including an entry for each permitted communication partner of the device having a first identifier that explicitly identifies the communication partner, a value of a predetermined certificate field that identifies a certificate as explicitly associated with the communication partner, and a respective check value from at least one certificate of a communication partner that explicitly identifies the certificate. A method for updating the positive list for certificates from permitted communication partners of a device comprises the method steps of receiving a new certificate from a communication partner in the device, checking whether the positive list has an entry having an identifier of the communication partner and a value of a predetermined certificate field from the new certificate.

Claims

1. A data structure for use as a positive list in a device, comprising:

an entry for each permitted communication partner of the device having

a first identifier that explicitly identifies the communication partner,

a value of a predetermined certificate field that identifies a certificate as explicitly associated with the communication partner, and

a respective check value from at least one certificate of a communication partner that explicitly identifies the certificate.

2. The data structure as claimed in claim 1, wherein the check value of a certificate is a value generated using a one-way function for the certificate.

3. The data structure as claimed in claim 1, wherein the first identifier and the value of the certificate field of all entries are digitally signed.

4. The data structure as claimed in claim 1, wherein the data structure at least intermittently contains a check value of an old certificate and a check value of a new certificate for a communication partner.

5. The data structure as claimed in claim 1, wherein the predetermined certificate field is the certificate holder.

6. The data structure as claimed in claim 1, wherein an entry for a permitted communication partner additionally contains the serial number of a device certificate of the communication partner.

7. A method for updating a positive list as claimed in claim 1 for certificates from permitted communication partners of a device, comprising:

receiving a new certificate from a communication partner in the device,

checking whether the positive list has an entry having an identifier of the communication partner and a value of a predetermined certificate field from the new certificate, and

including a new check value, which explicitly identifies the new certificate, in the positive list if the check on the positive list has yielded a positive result.

8. The method as claimed in claim 7, wherein the check value is ascertained from the received certificate by the device.

9. The method as claimed in claim 1, wherein the new certificate is included in the positive list only if the new certificate has been issued at a time after the old certificate.

10. The method as claimed in claim 1, wherein the new certificate is included in the positive list only if the new certificate and the old certificate have additionally been issued by the same certification center.

11. The method as claimed in claim 1, wherein the new certificate is included in the positive list only if the new certificate additionally contains the check value of the old certificate, in an attribute certificate.

12. The method as claimed in claim 1, wherein the new certificate is included in the positive list (10) only if the device is in a predetermined state.

13. The method as claimed in claim 1, wherein the new certificate is included in the positive list only if at least one prescribed subset of fields of the old certificate is contained in the new certificate.

14. The method as claimed in claim 1, wherein an updated check value is transmitted to the device via a connection authenticated using the old certificate, and the new check value is transmitted via a connection authenticated using the new certificate, and the new certificate is included in the positive list only if the new check value or a third check value derived from the new check value matches the updated check value.

15. The method as claimed in claim 1, wherein the device reports the new certificate of the communication partner to a monitoring apparatus, and the device initiates measures on receiving a negative check result from the monitoring apparatus.

16. The method as claimed in claim 1, wherein the new and old certificates are entered into the positive list as valid and the old certificate becomes invalid after a predeterminable period of time has passed or after a positive check result is received or the validity period of the old certificate has expired.

17. The method as claimed in claim 1, wherein the device uses an cryptographically protected, message to notify all communication partners cited in the positive list of the change of certificate of the communication partner.

18. The method as claimed in claim 1, wherein the communication partner, on a change of its certificate, additionally transmits its device certificate to the device for the purpose of authentication.

19. A device comprising an update unit, wherein the update unit is in such a form as to provide a positive list as claimed in claim 1.

20. The device as claimed in claim 19, wherein the device notifies all communication partners contained in the positive list of an update of its own certificate.

21. A computer program product, comprising a computer readable hardware storage device having computer readable program code stored therein, said program code executable by a processor of a computer system to implement a method loadable directly into a memory of a digital computer, comprising program code parts that are suitable for performing the steps of the method as claimed in claim 7.