Physical Unclonable Functions (PUFs) are considered attractive low-cost security anchors in the key generation scheme. The helper data algorithm is usually used to transform the fuzzy responses extracted from PUF into a reproducible key. The generated key can be used to encrypt secret data in traditional security schemes. In contrast, this work shows that the fuzzy responses of both weak and strong PUFs can be used to secretly store the important data (e.g., the distributed keys) directly by an error-tolerant algorithm, Fuzzy Vault, without the traditional encryption algorithm and helper data scheme. The locking and unlocking methods of our proposal are designed to leverage the feature of weak and strong PUFs relatively. For the strong PUFs, our proposal is a new train of thought about how to leverage the advantage of strong PUFs (exponential number of challenge-response pairs) when used in the field. The evaluation was performed on existing weak PUF and strong PUF designs. The unlocking rate and runtime are tested under different parameters and environments. The test results demonstrate that our proposal can reach a 100% unlocking rate by parameter adjustment with less than 1 second of locking time and a few seconds of unlocking time. Finally, the tradeoff between security, reliability, and overhead of the new proposal is discussed.
Keywords: Physical Unclonable Functions; error-tolerant; fuzzy pattern.