Secure Element Challenge Response Authentication Without MCU Random Generator

Solution Overview

Problem

Conventional challenge-response authentication processes for secure elements and micro controller units require internal random number generators, making them inflexible and costly, especially for low-cost systems.

Innovation Solution

A challenge-response authentication process where the micro controller unit generates a challenge datum using random data supplied by the secure element, eliminating the need for an internal random number generator in the micro controller unit, thereby reducing manufacturing costs and enabling secure communication in low-cost systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If internal random number generators are embedded in both the secure element and micro controller unit, then adequate security level is achieved, but manufacturing cost and device complexity increase

Engineering Contradiction:

Improvesecurity levelVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The random number generation function is extracted from the micro controller unit and relocated to the secure element. The secure element generates random challenge data that is then processed by the micro controller unit through cryptographic operations, eliminating the need for a separate random number generator in the micro controller unit while maintaining security requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The secure element is given a dual function: it serves both as the secure storage element and as the random number generator for the authentication protocol. By having the secure element generate the random challenge data, the system achieves adequate security without requiring separate random number generation capabilities in the micro controller unit.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If internal random number generators are embedded in both entities, then random challenge data generation is ensured, but manufacturing cost increases

Engineering Contradiction:

Improverandom challenge data generationVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The random number generation function is extracted from the micro controller unit and relocated to the secure element. The secure element generates random challenge data that is then processed by the micro controller unit through cryptographic operations, eliminating the need for a separate random number generator in the micro controller unit while maintaining security requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system uses the secure element's random number generation capability (which is already present for other security functions) to serve the additional purpose of generating authentication challenge data. This avoids the need for separate, expensive random number generator hardware in the micro controller unit.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If symmetric challenge-response authentication is implemented with both entities generating random data, then mutual authentication security is achieved, but the micro controller unit requires additional hardware components

Engineering Contradiction:

Improvemutual authentication securityVSAvoidhardware components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The random number generation function is extracted from the micro controller unit and relocated to the secure element. The secure element generates random challenge data that is then processed by the micro controller unit through cryptographic operations, eliminating the need for a separate random number generator in the micro controller unit while maintaining security requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The authentication protocol is made asymmetric in terms of random data generation: the secure element generates random challenge data while the micro controller unit generates random response data. This asymmetric approach maintains mutual authentication security while reducing hardware requirements in the micro controller unit.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS11146409B2Process for challenge response authentication of a secure element (SE) in a micro controller unit

Publication Date: 2021.10.12 IDEMIA FRANCE SAS

AI summary

Challenge-response authentication process of a secure element (SE) in a micro controller unit (MCU) devoid of a random number generator. The process includes the following steps conducted by the micro controller unit (MCU): receipt of at least one random datum (T, IDX) generated randomly by the secure element (SE), generation of a challenge datum (Z) specific to the micro controller unit (MCU) from the received random datum (T, IDX), sending of the generated challenge datum (Z) to the secure element (SE), receipt of a response datum (R) generated by the secure element (SE) as a function of the challenge datum (Z), and determination of an authentication result as a function of the received response datum.