Secure and Reliable Key Agreement with Physical Unclonable Functions

Area of Science:

• Applied Physics
• Cryptography
• Hardware Security

Background:

• Physical Unclonable Functions (PUFs) generate unique device identifiers from physical properties.
• Binding secret keys to these identifiers is crucial for secure authentication and device management.
• Existing methods face challenges in uniqueness, reliability, and hardware efficiency.

Purpose of the Study:

• To compare different transforms for binding secret keys to physical identifier outputs.
• To enhance the uniqueness, reliability, and security of extracted bit sequences.
• To minimize hardware area and information leakage while maximizing secret-key length.

Main Methods:

• Evaluated transforms using decorrelation efficiency as the primary metric.
• Applied scalar quantizers to transform outputs for uniform bit sequence extraction.
• Utilized ring oscillator (RO) outputs as physical identifiers.
• Proposed low-complexity error-correction codes for complete key-binding systems.

Main Results:

• Identified well-performing transforms that yield highly uncorrelated outputs.
• Demonstrated improved uniqueness and reliability of secret keys bound to RO outputs.
• Achieved reduced hardware area and information leakage.
• Showcased perfect secrecy and better secret-key and privacy-leakage rates compared to existing methods.
• Validated the transform-coding approach with a reference hardware implementation indicating small area.

Conclusions:

• Transform coding offers an efficient and secure method for binding secret keys to physical identifiers.
• The proposed approach enhances cryptographic security and device authentication.
• The method is hardware-efficient, making it suitable for resource-constrained environments.