Error Correction Schemes for Physical Unclonable Functions

Sven Müelich

Institute of Communications Engineering
Ulm University

Abstract:

Physical Unclonable Functions (PUFs) are, typically digital, circuits that possess an intrinsic randomness due to process variations which occur during manufacturing. They evaluate these variations and can therefore be used to extract bit sequences which can be used for cryptographic applications like identification, authentication or secure key generation. It is not necessary to store these keys in a protected memory since they are implicitly stored in the PUF and can be reproduced on demand. However, the results when reproducing a key vary, which can be interpreted as errors. Thus, error correction must be used in order to ensure proper operation. So far, there exist schemes that obtain helper data, which are needed within the error correction process. Recently, we introduced a new scheme, which only uses an error correcting code without any further helper data. The main idea of our scheme is to construct for each PUF instance an individual code which contains the initial PUF response as codeword. This approach simplifies the key reproduction process, since calculations based on helper data can be omitted and only decoding has to be performed.