Secure Key Provisioning via External Trusted Server

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Solution Overview

Problem

Existing key management systems for devices, such as System on Chip (SoC), are vulnerable to device cloning and impersonation attacks, as they rely on internal processes for key generation and verification, lacking robust external authentication mechanisms.

Innovation Solution

Implementing adapted asymmetric and symmetric key pair generation methods that require authentication from an external device, using a certificate authority to verify device identity and incorporating an external secure source for secret seed generation to ensure secure key provisioning, thereby preventing unauthorized access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If internal key generation and verification processes are used, then device operations are simplified and faster, but security is compromised due to vulnerability against device cloning and impersonation attacks

Engineering Contradiction:
ImprovesecurityVSAvoidkey provisioning process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a remote trusted server as an intermediary authority that performs certificate issuance and key verification. This mediator entity enables the device to obtain cryptographically verified certificates from an external trusted source, preventing device cloning attacks while maintaining operational simplicity through automated certificate validation processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary certificate issuance before key generation and usage. By obtaining and validating certificates from a remote trusted server prior to any cryptographic operations, the system ensures that keys are bound to authentic device identities from the outset, preventing impersonation attacks while streamlining the overall key management process.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If asymmetric key pairs are generated using standard PKI, then key management is automated, but device identity can be compromised by attackers who hack or attack the device

Engineering Contradiction:
Improvedevice identity securityVSAvoidkey provisioning
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The remote trusted server acts as an intermediary that issues certificates signed with a private key stored in a secure hardware module. This mediator ensures that even if the device is hacked, the attacker cannot generate valid certificates, as the private key remains protected in the hardware module while the server validates and issues certificates for authenticated devices only.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the certificate issuance and verification functions from the device itself and places them in a remote trusted server. This separation means the device does not hold the master private key, reducing the impact of device compromise while maintaining automated key management through the server's cryptographic services.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If symmetric keys are generated using key derivation functions, then key generation is efficient, but the keys can be compromised if the device is cloned or impersonated

Engineering Contradiction:
Improvekey protectionVSAvoidkey generation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The remote trusted server serves as an intermediary that provides authenticated seed values for key derivation functions. The server validates device identities and issues cryptographic seeds that are then used by the device to generate symmetric keys. This ensures key protection through authentication while maintaining efficient key generation through the use of cryptographic seed values.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary authentication and seed value issuance before key generation. By obtaining authenticated seeds from the remote trusted server prior to key derivation, the system ensures that even cloned devices cannot generate valid symmetric keys, while the efficient key derivation function maintains high productivity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3732821B1Secure provisioning of keys
Publication Date: 2023.11.08 NAGRAVISION SA
  • EP3732821B1 patent drawingFigure 1
  • EP3732821B1 patent drawingFigure 2
  • EP3732821B1 patent drawingFigure 3

AI summary

Methods and devices in accordance with the disclosure relate to the secure provision of one or more keys or key pairs to protect secret data for, or associated, with a computing device. The device is typically a computing device with at least one processor or processing module configured for executing one or more applications using the secret data. The present disclosure ensures secure key provisioning by ensuring that each key in a key pair, or at least one key among a plurality of keys is associated with a device or hardware module that is distinct to the device(s) or hardware module associated with the other or remaining keys. For asymmetric key provisioning, this relates to utilizing digital signatures verified by separate devices. For symmetric key provisioning, this relates to utilizing a secret key derivation function that will operates with secret seeds that are input from two separate sources.