Time-Variant Key Generation for IC Card Authentication Security
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Solution Overview
Problem
Existing authentication methods for IC cards are vulnerable to Differential Fault Analysis (DFA) attacks, which allow hackers to analyze and obtain the secret key by introducing faults during the encryption process, leading to potential illegal access.
Innovation Solution
An information processing device that generates a time-variant key based on a random number and uses it for encryption, transmitting the encrypted random number along with the original random number to the other device, making it difficult for attackers to deduce the secret key from multiple processing results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed key is used for encryption in authentication processing, then the authentication can be performed efficiently, but the system becomes vulnerable to Differential Fault_analysis (DFA) attacks that can deduce the secret key
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a fixed key to a time-variant key that changes with each authentication process. The key generation unit creates a new key based on the random number used in each authentication session, making the key dynamic rather than static. This prevents attackers from using DFA attacks to deduce a single fixed key, as each authentication uses a different key derived from the random number.
Solution Approach 2:
The patent applies parameter changes by modifying the key parameter from a fixed value to a variable value that depends on the random number. Instead of using a constant secret key, the system generates a key that changes its parameter values based on the random number used in each authentication session. This parameter variation makes it impossible for attackers to perform DFA attacks to determine a single key.
2Reliability
If a time-variant key is generated based on a random number for each authentication process, then resistance to DFA attacks is improved, but the processing complexity increases
Solution Approach 1:
The patent applies the self-service principle by having the key generation unit automatically generate the time-variant key based on the random number that is already part of the authentication process. The system uses the random number itself (which is necessary for authentication) to generate the key, eliminating the need for separate key management mechanisms. This self-service approach reduces the increase in processing complexity while maintaining security.
3Device complexity
If the same random number is used for both authentication and key generation, then the process is simplified, but the key derivation becomes more vulnerable to analysis
Solution Approach 1:
The patent applies the segmentation principle by separating the authentication function from the key generation function, even though both use the random number. The authentication unit performs authentication using the random number, while the key generation unit separately derives a time-variant key from the same random number. This segmentation allows each function to operate independently with appropriate security measures, preventing key derivation vulnerabilities while maintaining process simplicity.
Data Source
AI summary
An information processing device including a receiving unit that receives a first random number from another information processing device; a generating unit that generates a second random number; a time-variant-key generating unit that generates a time variant key for encryption according to the second random number; an encrypting unit that encrypts the first random number with the time variant key; and a transmitting unit that transmits the first random number encrypted by the time variant key and the second random number to the other information processing device.