Chip Encryption via Unique Fuse and Trim Values
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Solution Overview
Problem
Current cryptographic security chips are vulnerable to attacks due to the use of fixed encryption algorithms and secret keys, allowing crackers to easily access all secret keys and applications once one chip is cracked, leading to low-cost and easy cracking.
Innovation Solution
A method for chip encryption that utilizes unique fuse and trim values to set distinct encryption algorithms and secret keys for each chip, storing these values in internal storage, and optionally fusing a fuse wire to prevent reversibility, increasing the difficulty and cost of cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed encryption algorithm and secret key are used in cryptographic security chips, then the encryption operation is simple and efficient, but the chip becomes vulnerable to attacks and cracking
Solution Approach 1:
The patent applies local quality by making each chip have unique local characteristics through fuse values and trim values that are specific to individual chips or batches. These local differences create unique encryption parameters for each chip, so that cracking one chip does not compromise other chips, while the encryption operation remains simple using standard algorithms.
Solution Approach 2:
The patent changes the encryption parameters (secret keys and algorithm specifics) based on physical characteristics of each chip such as fuse values and trim values. This allows the use of simple, fixed encryption algorithms while achieving security through parameter variation, resolving the contradiction between operational simplicity and security.
2Productivity
If the same secret key is solidified into the chip during design, then the encryption algorithm can be efficiently implemented, but all chips in a batch become vulnerable once one chip is cracked
Solution Approach 1:
The patent segments the secret key generation process by incorporating chip-specific physical characteristics (fuse values, trim values) into the key derivation. This segmentation ensures that each chip has a unique secret key derived from its own physical properties, so that cracking one chip does not affect other chips in the batch, while maintaining efficient encryption processing.
Solution Approach 2:
The patent performs preliminary action by embedding unique physical characteristics (fuse values and trim values) into each chip during manufacturing before the chip is deployed. These pre-established physical differences are then used to generate unique encryption parameters, preventing batch-wide compromise even if one chip is cracked.
3Reliability
If fuse values and trim values are used to set unique encryption parameters for each chip, then chip security is enhanced and cracking cost increases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies self-service by using physical characteristics that naturally occur during standard manufacturing processes (fuse values from programming operations, trim values from analog circuit trimming). These characteristics are automatically generated as part of normal chip manufacturing and testing, requiring no additional complex manufacturing steps while providing unique identification and encryption parameters for each chip.
Data Source
AI summary
A method for chip encryption includes obtaining a fuse value and a trim value of a chip and setting an encryption algorithm, setting the fuse value and the trim value as parameters of the encryption algorithm and obtaining a secret key which is unique for the chip accordingly to the encryption algorithm, and storing the fuse value, the trim value and the secret key in the chip. Since the fuse value and trim value of the chip are unique naturally, the secret key obtained from the same matrix chip for different applications or different matrix chips for the same application are different from each other, thereby increasing expenses and difficulty for crackers to crack the chip and protecting user's intellectual property perfectly.