Overview[1]#

HOTP is an HMAC-based One Time Password Algorithm. It is a cornerstone of Initiative For Open Authentication Initiative for Open Authentication.

HOTP was published as an informational RFC 4226 in December 2005, documenting the algorithm along with a Java implementation.

Since then, the HOTP algorithm has been adopted by many companies worldwide.

The HOTP algorithm is a freely available open standard.

More Information#

There might be more information for this subject on one of the following:

• Authenticator App
• Google Authenticator
• HMAC-based One-Time Password Algorithm
• One-Time password
• One-time password device tokens
• Time-based One-time Password Algorithm
• YubiKey

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• [#1] - HMAC-based One Time Password algorithm - based on 2015-02-12.