Semiconductor Cryptographic Key Generation Using Unique Codes
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Solution Overview
Problem
Existing cryptographic communication systems face challenges in securely sharing common keys between semiconductor devices without third-party access and verifying the authenticity of added devices, leading to potential data leakage and increased costs due to the need for expensive secure servers.
Innovation Solution
The system generates unique codes from process variations, corrects them using specific data, and encrypts common keys for secure transmission, allowing semiconductor devices to establish secure communication without direct storage of sensitive keys and eliminating the need for expensive secure servers by using general-purpose microcomputers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common keys are stored in nonvolatile memory of semiconductor devices, then cryptographic communication can be established, but data leakage occurs during unauthorized analysis
Solution Approach 1:
The patent extracts the sensitive secret key from the semiconductor device memory. Instead of storing the secret key SK(y) in the device, only the common key CK(x) is stored. The secret key is generated and used temporarily for decryption, then discarded. This extraction eliminates the security vulnerability of storing sensitive keys in nonvolatile memory.
Solution Approach 2:
The patent segments the cryptographic key structure into two parts: the common key CK(x) that is stored in the device, and the secret key SK(y) that is generated temporarily and not stored. This segmentation allows the device to maintain cryptographic functionality while avoiding the storage of highly sensitive secret keys that would be vulnerable to unauthorized analysis.
2Reliability
If expensive secure servers are incorporated to verify added semiconductor devices, then device authenticity can be verified, but system costs increase
Solution Approach 1:
The patent implements self-service verification where the semiconductor device itself verifies its own authenticity through the unique relationship between its stored common key CK(x) and its generated secret key SK(y). When a device needs to be added to the network, it can prove its authenticity by demonstrating knowledge of both keys without requiring external verification infrastructure. This eliminates the need for expensive secure servers.
Solution Approach 2:
The patent makes the common key CK(x) serve multiple functions: it is used for both encryption of data and for verification of device authenticity. This multi-functionality eliminates the need for separate verification infrastructure, allowing general-purpose microcomputers to replace expensive secure servers while maintaining security and verification capabilities.
Data Source
AI summary
Provided is a cryptographic communication system including a first semiconductor device and a second semiconductor device. The first semiconductor device includes a common key generation unit that generates a common key CK(a) by using a unique code UC(a) and correction data CD(a), and an encryption unit that encrypts the common key CK(a) generated in the common key generation unit by using a public key PK(b) of the second semiconductor device. The second semiconductor device includes a secret key generation unit that generates a secret key SK(b) by using a unique code UC(b) and correction data CD(b), and a decryption unit that decrypts the common key CK(a) encrypted in the encryption unit by using the secret key SK(b).