Construction of Software-Based Digital Physical Clone Resistant Functions

Due to the emerging sophisticated physical attacks on security systems, secure authentication of electronic devices becomes more difficult to attain. Recent research showed alarming vulnerabilities in existing cryptographic systems through side channel and (semi)-invasive attacks. The main challenging problem is the break one break all phenomena. As if one successful attack is found, then it may be deployed automatically on any units incorporating similar implementations. Physical Unclonable Functions (PUFs) were introduced as promising solutions to provide resilient device authentication. However, recent research on PUFs showed that PUFs exhibit several implementation complexity, inconsistency and security drawbacks for long-term use. PUF structures, especially for existing microcontroller low-cost applications showed serious drawbacks and cloning vulnerabilities. The objective of this work is to propose a digital PUF alternative by pure software entities with robustness to side channel attacks. The resulting implementation size is comparable to lightweight cryptographic algorithms. The key implementation idea is based on self-creation of secret unknown cryptographic functions. As the implementation is pure digital, no inconsistency compared to that of conventional PUFs is possible and the resulting system would exhibit a long-term resilient consistency. Due to their pure software implementation the cost per unit may reach zero which is quite attractive for practical cloning-protection in many massproduct applications.