Abstract: Challenge-response can be a secure way of protecting access to any privileged material if implemented correctly. In this document, many options for challenge-response access control are discussed but the most secure method given is presenting a different random challenge on each access attempt and having a response that only the host can interpret without giving out any secrets. This document shows why Maxim’s SHA-1 iButtons® and 1-Wire devices are ideal choices when implementing this kind of challenge-response system. Maxim > App Notes > 1-Wire Devices iButton Security and Authentication Keywords: challenge-response, challenge, random challenge, response, SHA, SHA-1, MAC, coprocessor, user, access control, Mar 12, 2002 authentication, ecash, web access, random number generator, DS1963S, DS1961S, DS2432, software piracy APPLICATION NOTE 190 Challenge and Response with 1-Wire SHA Devices Abstract:Challenge-response can be a secure way of protecting access to any privileged material if implemented correctly. In this document, many options for challenge-response access control are discussed but the most secure method given is presenting a different random challenge on each access attempt and having a response that only the host can interpret without giving out any secrets. This document shows why M……