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1. (WO2018024423) FORMING A PLURALITY OF ALTERNATIVE SECRETS ON A COMPONENT AND USING A PLURALITY OF ALTERNATIVE SECRETS IN A CHALLENGE-RESPONSE METHOD

Pub. No.:    WO/2018/024423    International Application No.:    PCT/EP2017/066543
Publication Date: Fri Feb 09 00:59:59 CET 2018 International Filing Date: Wed Jul 05 01:59:59 CEST 2017
IPC: H04L 9/08
H04L 9/32
H04L 9/00
Applicants: SIEMENS AKTIENGESELLSCHAFT
Inventors: ASCHAUER, Hans
MERLI, Dominik
Title: FORMING A PLURALITY OF ALTERNATIVE SECRETS ON A COMPONENT AND USING A PLURALITY OF ALTERNATIVE SECRETS IN A CHALLENGE-RESPONSE METHOD
Abstract:
The invention relates to a method for forming a plurality of alternative secrets on a component, wherein properties of the component are measured by means of a physically unclonable function and results are determined from the measured properties, wherein the results are evaluated with respect to reliability and are evaluated as reliable or unreliable by comparing the measured properties with respective threshold values, wherein, for results evaluated as unreliable, alternative results are provided, and wherein a plurality of alternative secrets is formed from the results evaluated as reliable and from the alternative results and a number of alternative secrets is defined at least by a number of possible combinations of the alternative secrets. Furthermore, by means of alternative secrets, a challenge-response method is realized which sends, as responses, a plurality of alternative responses formed from the alternative secrets as answers to a challenge. In an advantageous manner, a probability that a certain measurement result was determined incorrectly is estimated by analyzing and evaluating the reliability of individual results. These potentially incorrectly determined results are considered with all potentially determinable alternatives and thus lead to an optimized brute-force strategy for an error-tolerant calculation of a cryptographic function.