Biblio

In the era of big data, information security is faced with many threats, among which memory data security of intelligent devices is an important link. Attackers can read the memory of specific devices, and then steal secrets, alter data, affect the operation of intelligent devices, and bring security threats. Data security is usually protected by encryption algorithm for device ciphertext conversion, so the safe generation and use of key becomes particularly important. In this paper, based on the advantages of SRAM PUF, such as real-time generation, power failure and disappearance, safety and reliability, a key generation unit is designed and implemented. BCH code is used as the error correction algorithm to generate 128-bit stable key, which provides a guarantee for the safe storage of intelligent devices.

Physical unclonable functions(PUFs) are widely used as hardware root-of-trust to secure IoT devices, data and services. A PUF exploits inherent randomness introduced during manufacturing to give a unique digital fingerprint. Static Random-Access Memory (SRAM) based PUFs can be used as a mature technology for authentication. An SRAM with a number of SRAM cells gives an unrepeatable and random pattern of 0's and 1's during power on. As it is a unique pattern, it can be called as SRAM fingerprint and can be used as a PUF. The chance of producing more number of same values (either zero or one) is higher during power on. If a particular value present at almost all the cell during power on, it will lead to the dominance of either zero or one in the cryptographic key sequence. As the cryptographic key is generated by randomly taking address location of SRAM cells, (the subset of power on values of all the SRAM cells)the probability of occurring the same sequence most of the time is higher. In order to avoid that situation, SRAM should have to produce an equal number of zeros and ones during power on. SRAM PUF is implemented in Cadence Virtuoso tool. To generate equal zeros and ones during power on, variations can be done in the physical dimensions and to increase the stability body biasing can be effectively done.

This paper provides a proof of concept for using SRAM based Physically Unclonable Functions (PUFs) to generate private keys for IoT devices. PUFs are utilized, as there is inadequate protection for secret keys stored in the memory of the IoT devices. We utilize a custom-made Arduino mega shield to extract the fingerprint from SRAM chip on demand. We utilize the concepts of ternary states to exclude the cells which are easily prone to flip, allowing us to extract stable bits from the fingerprint of the SRAM. Using the custom-made software for our SRAM device, we can control the error rate of the PUF to achieve an adjustable memory-based PUF for key generation. We utilize several fuzzy extractor techniques based on using different error correction coding methods to generate secret keys from the SRAM PUF, and study the trade-off between the false authentication rate and false rejection rate of the PUF.