BACKGROUND

Physical Unclonable Functions (PUFs) are integrated circuits that are used to securely authenticate devices or generate cryptographic keys without using non-volatile memories. PUFs harvest natural randomness in manufacturing process variations in order to generate random yet unique bits. With embedded devices becoming more ubiquitous, these low-power, low-area and low-cost hardware security primitives have received extensive attention in research and commercial communities. PUFs can be categorized as strong or weak PUFs based on whether the number of unique input challenges is large or small, respectively. Unpredictability, reliability, uniqueness and randomness are fundamental characteristics of PUFs. Two of the biggest issues that strong PUFs face are low reliability and vulnerability to attacks. Unpredictability ensures resilience against cloning attacks. One major issue with standard PUFs is that these can be described by linear models which can be learned easily.

The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.

SUMMARY

An apparatus includes a first feed-forward PUF, a second feed-forward PUF and an exclusive-or circuit configured to perform an exclusive-or operation of an output of the first feed-forward PUF and an output of the second feed-forward PUF.

In accordance with a further embodiment, a method includes executing a first feed-forward PUF to produce a first response, executing a second feed-forward PUF to produce a second response and applying the first response and the second response to an exclusive-or circuit to produce an XOR response.

In a still further embodiment, an integrated circuit includes a plurality of feed-forward PUFs, each providing a separate response and an exclusive-or circuit applying an exclusive-or operation to the separate responses to produce an exclusive-or response.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

