I am happy to announce a project that I have been working quietly on for about a year: the OATH Toolkit. OATH stands for Open AuTHentication and is an organization that specify standards around authentication. That is a pretty broad focus, but practically it has translated into work on specifying standards around deploying and using electronic token based user authentication such as the YubiKey.
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OATH’s most visible specification has been the HOTP algorithm which is a way to generate event-based one-time passwords from a shared secret using HMAC-SHA1. HOTP has been published through the IETF as RFC 4226. Built on top of HOTP is the time-based variant called TOTP, which requires a clock in the token. OATH do some other work too, like specifying a data format for transferring the token configuration data (e.g., serial number and shared secret) called PSKC.
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