טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentNishry Oren
SubjectPUF:Survey on Physical Unclonable Function Hardware
Implementation and Security-Based Application
DepartmentDepartment of Electrical Engineering
Supervisor Professor Avi Mendelson
Full Thesis textFull thesis text - English Version


Abstract

Physical Unclonable Functions emerged over the last decade in hardware chip design as a promise for small area and efficient security application methods such as chip authentication, or unique key generation. The use of circuit which supports security operations in a low power consumption with low-cost integration appeal to many modern chip design platforms such as mobile, IoT or automotive where are either limited by area or by battery life and requires communicating over network which may be exposed to adversary attacks.
    As the name suggests PUF circuit uses a physical function to map between a challenge and response, the mapping is done using some stimulus to the digital circuit where due to process variations it is expected to receive for the same challenge a different response across different devices - known as uniqueness of PUF, and the same response for the same device across different environmental settings - known as reliability of PUF. The statistical proprieties (such as uniqueness and reliability) tells how “good” a PUF behaves however that is not enough to tell if it is feasible to use a PUF circuit as a security primitive since additional questions are needed to be answered: Is the PUF secure against adversary attacks, such as modeling? Is PUF implementation in terms of area as low as it is promised? Since PUF response is subject to random process variations how good it`s reliability as device ages?
   This work tries to answer above questions while giving a complete survey of different PUF architectures and summarize a “rule of thumb” for PUF as a security primitive. In addition, we performed an aging experiment for 40nm Arbiter PUF, Arbiter PUF is mostly used as a building block for authentication protocols. The experiment reinforces our assumption that as process node shrinks, PUF circuit is more prone to aging affect which results in decreased reliability. Power reliability over time requires either mitigation or the use of other PUF architecture than Arbiter PUF as a building block for authentication protocols.