Validity Registers for Public Key Authentication in Cryptographic Devices

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Solution Overview

Problem

Cryptographic systems face inefficiencies due to the need for repeated verification of public key authenticity in every transaction, particularly in high-performance computers that lack secure storage for verification status, leading to increased computational complexity and latency.

Innovation Solution

A cryptographic device with a memory structure and controller that stores public keys and their authentication status in a validity register, allowing exclusive write access to ensure authentication status is securely stored and retrieved, thereby reducing the need for repeated authentication checks during cryptographic operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If repeated verification of public key authenticity is performed in every transaction, then security is improved, but computational complexity and latency increase

Engineering Contradiction:

Improvepublic key authentication securityVSAvoidcomputational complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs public key authentication in advance during key loading or initialization, and stores the authentication status in a validity register. This preliminary authentication eliminates the need for repeated verification in subsequent transactions, reducing computational complexity while maintaining security.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The validity register provides feedback about the authentication status of a public key to the cryptographic operations. When a public key is loaded or updated, the system checks the validity register and only performs cryptographic operations if the key is authenticated, creating a feedback loop that optimizes security without redundant verification.

Inventive Principle:

Principle #23Feedback

2Reliability

If repeated verification of public key authenticity is performed in every transaction, then security is improved, but transaction latency increases

Engineering Contradiction:

Improvepublic key authentication securityVSAvoidtransaction latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Authentication is performed once during key loading or initialization rather than repeatedly in each transaction. The validity register stores the authentication result, allowing transactions to proceed without time-consuming re-verification, thus reducing latency while maintaining security.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The validity register enables the system to remember and reuse authentication results automatically. The cryptographic device can check its own validity status without external intervention, eliminating the need for repeated authentication calls and reducing transaction time.

Inventive Principle:

Principle #25Self-service

3Productivity

If authentication status is stored in memory, then verification efficiency is improved, but security risks increase if the storage is compromised

Engineering Contradiction:

Improveverification efficiencyVSAvoidsecurity risks from memory compromise

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The validity register acts as a secure intermediary between the authentication process and cryptographic operations. It stores authentication status in a protected location within the cryptographic device, accessible only through controlled read operations, thus enabling efficient verification while minimizing security risks from memory compromise.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The validity register is a simple, dedicated storage structure that holds only the authentication status bit. This minimalistic approach reduces the attack surface compared to storing full authentication data, and the register can be securely reset or rewritten when needed without exposing sensitive information.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Reliability

If exclusive write access to validity register is implemented, then authentication status integrity is improved, but device complexity increases

Engineering Contradiction:

Improveauthentication status integrityVSAvoidaccess control complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The validity register is designed with specialized access control properties: the controller has exclusive write access to maintain integrity, while the host has read-only access to check status. This localized differentiation of access rights ensures authentication status integrity without requiring complex system-wide access control mechanisms.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8909929B2Stored public key validity registers for cryptographic devices and systems

Publication Date: 2014.12.09 ATMEL CORP

AI summary

Systems and techniques for performing cryptographic operations based on public key validity registers are described. A described system includes a controller and a memory structure to store one or more public keys. The memory structure includes one or more validity registers that respectively correspond to the one or more public keys. The controller has exclusive write access to the validity register. The controller can be configured to perform an authentication of a public key, write an authentication status value to the corresponding validity register based on a result of the authentication, and perform one or more cryptographic operations using the public key that are conditional on the validity register indicating an authenticated status for the public key.