Cryptographic Key Covering Microstructure for Tamper Response

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Solution Overview

Problem

Existing cryptographic key security mechanisms are vulnerable to unauthorized access and tampering, especially when signature-computing hardware devices are transported or exposed to malicious users, as tamper-proof chips are not foolproof and can be compromised by probes.

Innovation Solution

A security device with a covering device that provides a random output signal based on its microstructure, a key generation component, and a digital signature component, surrounded by a protective layer to prevent unauthorized access, ensuring the microstructure alters with any attempt to access the components, and the secret key exists only long enough to sign a message.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a tamper-proof chip is used to store the secret key, then the security against unauthorized access is improved, but the chip can still be compromised by probes and is not absolutely tamper-proof

Engineering Contradiction:

Improvesecurity against unauthorized accessVSAvoidvulnerability to probing attacks

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of physical tampering into a beneficial security mechanism. When the covering device is accessed or tampered with, the microstructure changes, which automatically alters the random output signal and invalidates the secret key. This transforms the physical attack into a self-destruct mechanism that protects the key.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the physical parameter of the covering device's microstructure in response to tampering. The microstructure serves as a physical state that determines the random output signal. When tampering occurs, the microstructure parameter changes, which in turn changes the output signal and renders the secret key useless.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the secret key is stored in hardware that can be transported, then the versatility and usability are improved, but the device becomes vulnerable to malicious users during transport

Engineering Contradiction:

Improveportability and usabilityVSAvoidexposure to malicious users during transport

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent enables portable hardware devices to maintain security during transport by converting the risk of exposure to malicious users into a protective mechanism. The covering device's microstructure, which may be altered during transport or attempted access, automatically changes the random output signal, ensuring that even if the device is stolen or accessed, the secret key cannot be extracted or reused.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the microstructure of the covering device is used to generate random output, then the security against key extraction is improved, but any access attempt alters the microstructure and invalidates the key

Engineering Contradiction:

Improveprotection against key extractionVSAvoidoperational stability of the key

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements preliminary action by pre-establishing the covering device with its microstructure that will serve as the basis for the random output signal. The system is designed in advance so that any future access attempt will automatically alter the microstructure and invalidate the key, preventing key extraction before it can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the potential harm of microstructure alteration during access attempts into a beneficial security feature. The alteration of microstructure, which might be seen as a degradation or error, is instead used to automatically change the random output signal and invalidate the secret key, preventing unauthorized access.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12506621B2Securing cryptographic keys

Publication Date: 2025.12.23 MICALI DR SILVIO

AI summary

A security device includes a covering device that, in response to an input signal, consistently provides a same random output signal that varies according to the microstructure of the covering device, where altering the microstructure of the covering device alters the random output signal, a key generation component that generates a secret key based on the random output signal, and a digital signature component that produces a digital signature of a message received by the security device using the secret key. The covering device surrounds at least a portion of the key generation component and the digital signature component to prevent access thereto and where accessing any of the components alters the microstructure of the covering device to alter the random output signal. The security device may be attached to an object and detaching the security device from the object may alter the microstructure of the covering device.