Portable Data Carrier Security Against Side-Channel Attacks
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Solution Overview
Problem
Portable data carriers, such as chip cards, are vulnerable to side-channel attacks like Simple Power Analysis (SPA) and Differential Power Analysis (DPA), which infer security-critical data by measuring physical parameters during program execution, as existing methods using random wait states do not effectively protect against these attacks.
Innovation Solution
Implementing random wait states where the processing unit computes and compares checksums over selected memory regions to verify data integrity, using cryptographic methods like CRC or hash functions, instead of idle loops, to disrupt power curve synchronization and enhance attack resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random wait states are inserted into command processing to thwart SPA/DPA attacks, then security against side-channel attacks is improved, but the processing time and productivity deteriorate
Solution Approach 1:
The processing unit performs checksum computation continuously during random wait states instead of idle looping. This utilizes the wait time productively to verify data integrity while maintaining the random timing pattern that disrupts power analysis attacks, thereby improving security without additional time penalty.
Solution Approach 2:
The system uses its own processing capacity during wait states to perform self-diagnosis through checksum verification. The processing unit serves itself by checking data integrity in memory regions during periods when it would otherwise be idle, eliminating the need for separate verification steps.
2Reliability
If random wait states with idle loops are used to disrupt power curve synchronization, then security against SPA/DPA attacks is improved, but the device complexity increases
Solution Approach 1:
The processing unit is designed to perform multiple functions: normal command processing, random wait state generation, and checksum computation. By making the processing unit multi-functional, the patent avoids adding separate hardware components for security operations, thereby improving security while minimizing increases in device complexity.
Solution Approach 2:
The patent combines the security function (random wait states) with the data integrity verification function (checksum computation) into a single operational phase. This merging of functions allows the system to achieve multiple security objectives simultaneously without requiring separate operational modes or additional complex control logic.
3Measurement precision
If checksum computation is performed during random wait states to verify data integrity, then detection of corrupted data is improved, but the processing time for each command increases
Solution Approach 1:
The system performs checksum computation during random wait states that occur between command processing steps. By utilizing these pre-existing wait periods for data verification, the patent implements data integrity checking without adding time to the core command processing path, as the verification occurs in parallel with the random timing disruption.
Data Source
AI summary
A method for operating a portable data carrier includes a processing unit for processing commands and a memory unit for storing data, with random wait states being inserted into the processing of the commands for thwarting SPA/DPA attacks. An actual checksum may be computed over the data of a selected region of the memory unit during a random wait state. A portable data carrier is arranged for executing the method.