Method for secure usage of cryptographic material

Patent metadata

Field	Value
Publication number	US-11764957-B2
Application number	US-202117926718-A
Country	US
Kind code	B2
Filing date	May 7, 2021
Priority date	May 22, 2020
Publication date	Sep 19, 2023
Grant date	Sep 19, 2023

Abstract

A method for secure usage of cryptographic material in networked system components provided with the cryptographic material in which a lifecycle of every system component includes at least one development phase and one production phase. The entire cryptographic material is at least directly securely marked as development or production material. Each system component has a binary state flag showing which phase the system component is in and which is secured against unauthorized manipulation. Each system component determines via an assessment function which phase it is in, according to which each system component carries out a check, during which the current phase and the marker of the cryptographic material are compared. Security measures are introduced if there is no agreement between the phase and the marker.

First claim

The invention claimed is:

1. A method for secure usage of cryptographic material in several system components of a networked system that are provided with the cryptographic material, wherein the lifecycle of every system component comprises at least one development phase and one production phase, the method comprising:
at least directly securely marking the entire cryptographic material as development or production material, wherein each of the several system components comprises a binary state flag showing which phase the system component is in, wherein the binary state flag is secured against unauthorized manipulation;
determining, by each of the several system components, using an assessment function, a current phase that the respective one of the several system components is in;
checking, by each of the several system components, by comparing the current phase and a marker of the cryptographic material, wherein the marker of the cryptographic material indicates whether the cryptographic material is development phase cryptographic material or production phase cryptographic material; and
introducing security measures when the check indicates that there is no agreement between the current phase and the marker, wherein
the checking is performed a first time the several system components are booted up after preparing the cryptographic material or when the cryptographic material is being prepared for the respective system component in the system component, and
the system component performs a plausibility test for the production phase if the assessment function determines that the system component is in the production phase, for which purpose predetermined conditions for the production phase are checked, wherein if at least one of the predetermined conditions is not fulfilled, security measures are introduced.

2. The method of claim 1 , wherein the marker of the cryptographic material or the binary state flag is secured via cryptographic measures.

3. The method of claim 2 , wherein the binary state flag is secured in a memory that can only be written once or is secured in a hardware security module.

4. The method of claim 1 , wherein the checking occurs in the system component.

5. The method of claim 1 , wherein the plausibility test occurs before the first checking and after the preparation of the cryptographic material, or before the cryptographic material is prepared for the respective system component in the respective system component.

6. The method of claim 1 , wherein the security measures comprise at least one warning message.

7. The method of claim 1 , wherein the security measures comprise a halting or a prevention of the preparation of the cryptographic material, wherein non-matching cryptographic material that is potentially already introduced is securely deleted in the system component.

8. The method of claim 1 , wherein the security measures comprise stopping implementation of the system component.

9. The method of claim 1 , wherein the networked system is a vehicle ecosystem.

Assignees

• Mercedes Benz Group Ag

Inventors

• Friesen Viktor
• Pavlovic Viktor

Classifications

• G06F21/64 Primary

  Protecting data integrity, e.g. using checksums, certificates or signatures · CPC title

• H04L9/088 Primary

  Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms (network architectures or network communication protocols for using time-dependent keys in a packet data network H04L63/068) · CPC title

• H04L9/3263

  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 title

• H04L9/3247

  involving digital signatures · CPC title

• H04L9/0897

  involving additional devices, e.g. trusted platform module [TPM], smartcard or USB · CPC title