Encryption Key Reading System Laser Attack Protection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing key reading systems are vulnerable to attacks using lasers, which can force the delivery of encryption/deciphering keys by manipulating the logical state of multiplexers.

Innovation Solution

A process and system for reading an encryption/deciphering key that requires two different conditions to be met, involving comparisons of bits from an unlock word and an access key, and utilizing multiple means of deliverance to ensure key integrity during attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single comparator and single set of multiplexers are used to read the encryption/decryption key, then the system operation is simple and fast, but the system becomes vulnerable to laser attacks that can force key delivery by manipulating the logical state

Engineering Contradiction:
Improveresistance to laser attacksVSAvoidnumber of comparators and delivery means
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the key reading operation into multiple independent segments: multiple comparators (first comparator, second comparator) each comparing different sets of bits, and multiple delivery means (first multiplexer, second multiplexer) each delivering different portions of the key. This segmentation ensures that a laser attack on one segment does not compromise the entire key, as each segment operates independently and requires separate manipulation to force delivery.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple sets of bits are compared under different conditions to deliver the key, then the system becomes more robust against attacks, but the reading process requires more steps and time

Engineering Contradiction:
Improvesecurity against laser attacksVSAvoidkey reading time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary comparisons of different sets of bits under different conditions before the actual key delivery is required. The first comparator compares a first set of bits under a first condition, and the second comparator compares a second set of bits under a second condition, preparing the system in advance so that when the correct conditions are met, the key can be delivered securely without requiring sequential manipulation during the attack window.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4539386A1System for reading an encryption/decryption key and method thereof
Publication Date: 2025.04.16 STMICROELECTRONICS INT NV
  • EP4539386A1 patent drawingFigure 1
  • EP4539386A1 patent drawingFigure 2
  • EP4539386A1 patent drawingFigure 3

AI summary

The encryption/decryption key reading system (10) comprises at least a first word (32) comprising a plurality of bits (B31, B32, B33, B34, B35, B36, B37, B38), the system comprising: - a first means of comparison (21), - a first means of delivery (12), - a second means of comparison (22), and - a second means of delivery (13).