PROTECTION OF SOFTWARE MODELS

• US 20160112195A1
• Filed: 10/19/2015
• Published: 04/21/2016
• Est. Priority Date: 10/20/2014
• Status: Active Grant

• Current Assignee: Dspace GmbH
• Original Assignee: Dspace Digital Signal Processing And Control Engineering Gmbh
• Inventors: KRUEGEL, Karsten, BLOEMER, Johannes, JOCHHEIM, Janek, LISKE, Gennadij
• Granted Patent: US 10,554,404 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 8/35 model driven
• CPC Class Codes: H04L 9/007 involving hierarchical structures
• CPC Class Codes: H04L 9/0816 Key establishment, i.e. cryptographic processes or cryptographic protocols whereby a shared secret becomes available to two or more parties, for subsequent use
• CPC Class Codes: H04L 9/14 using a plurality of keys or algorithms
• CPC Class Codes: H04L 9/30 Public key, i.e. encryption algorithm being computationally infeasible to invert or user's encryption keys not requiring secrecy

Abstract

An encryption method is provided that has a software model of a technical system, the model including software components is encrypted by a public key and a decryption structure, wherein the latter includes definitions of component groups of the software model. The decryption structure is integrated at least partially into the encrypted software model. Correspondingly, in a decryption method according to the invention, via a secret key that likewise comprises definitions of component groups, only the particular component groups are decrypted whose definitions the secret key includes in agreement with the definitions of the encrypted software model. The definitions of the secret key can be extended after the fact by a key extension, so that additional component groups can be decrypted with an extended secret key.

Claims

1. A method for encrypting a software model having software components of a technical system, a control unit and/or a system controlled or regulated by a control unit, the method comprising:

generating a public key and a master key;

generating a decryption structure that includes at least one definition of a component group of the software components of the software model;

at least partially encrypting the software model via the public key; and

at least partially integrating the decryption structure into the encrypted software model such that the at least one component group is only decryptable via a secret key that includes the definition of the at least one component group.

2. The method according to claim 1, wherein the decryption structure is generated by assigning attributes to the software components and defining at least one component group from those software components to which at least one specific attribute was assigned.

3. The method according to claim 2, wherein the software components within the software model are in hierarchical relationship with one another, wherein attributes are assigned to the software components such that each software component possesses at least one attribute in common with a hierarchically higher-level software component.

4. The method according to claim 1, wherein the software components within the software model are in hierarchical relationship with one another, wherein the decryption structure is generated such that a component group also includes a hierarchically higher-level software component for each software component.

5. The method according to claim 1, wherein the decryption structure is generated such that the at least one component group forms an autonomous part of the software model.

6. The method according to claim 1, wherein the software model comprises trivial software components and/or essential software components, wherein the decryption structure is generated such that the at least one component group includes all trivial software components and/or all essential software components.

7. The method according to claim 1, further comprising:

generating the at least one secret key via the master key and the decryption structure such that the secret key includes the definition of the at least one component group.

8. The method according to claim 7, wherein the at least one specific attribute is integrated into the secret key during generation of the secret key.

9. The method according to claim 1, further comprising:

generating an additional decryption structure that defines at least one additional component group of software components of the software model;

generating a key extension for the at least one secret key via the master key and the additional decryption structure such that the key extension includes the definition of the at least one additional component group.

10. The method according to claim 9, wherein the additional decryption structure is generated by defining at least one additional component group from the software components to which at least one specific additional attribute has been assigned, and wherein the at least one additional specific attribute is integrated into the key extension during generation of the key extension.

11. The method according to claim 9, wherein an identifier of the secret key is integrated into the key extension during generation of the key extension.

12. The method according to claim 9, wherein the key extension is generated such that the at least one additional component group is only decryptable by an extended secret key that is composed of the secret key and the key extension.

13. A method for decrypting a software model encrypted using a method according to claim 1 via a generated secret key, wherein the at least one component group is only decrypted if the decryption structure at least partially integrated into the encrypted software model defines the at least one component group and the secret key includes the definition of the at least one component group.

14. The method according to claim 13, wherein, for the purpose of decrypting the encrypted software model by the secret key, a check is made as to whether at least the at least one predefined attribute that is integrated into the secret key is assigned to a software component of the encrypted software model.

15. The method according to claim 13, wherein an extended secret key is formed from the secret key and the generated key extension, wherein the definition of the at least one additional component group is integrated into the secret key such that the at least one additional component group is decrypted via the extended secret key if a decryption structure at least partially integrated into the encrypted software model defines the at least one additional component group.

16. The method according to claim 15, wherein the at least one additional specific attribute is integrated into the secret key when the extended secret key is formed.

17. The method according to claim 15, wherein an identifier of the key extension and an identifier of the secret key are integrated into the extended secret key during formation of the extended secret key, wherein the at least one component group is only decrypted via the extended secret key if the identifier of the key extension and the identifier of the secret key correspond to one another.

18. An electronic data set comprising:

a software model that comprises software components and that is encrypted using the method according to claim 1; and

a decryption structure that defines at least one component group of software components of the software model,

wherein the data set is designed such that the encrypted software model is decryptable.

19. An encryption unit configured to encrypt a software model comprising software components using the method according to claim 1.

20. A decryption unit configured to decrypt an encrypted software model comprising software components using the method according to claim 13.

21. A development environment for developing a software model comprising software components, the environment comprising an encryption unit according to claim 19 and/or a decryption unit.