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OATH Toolkit
One-time password components
2020-11-11: OATH Toolkit 2.6.4 Released

Read the NEWS file for release highlights and a full list of changes. See the Download page for download links.

Simon Josefsson


The OATH Toolkit provide components for building one-time password authentication systems. It contains shared libraries, command line tools and a PAM module. Supported technologies include the event-based HOTP algorithm (RFC4226) and the time-based TOTP algorithm (RFC6238). OATH stands for Open AuTHentication, which is the organization that specify the algorithms. For managing secret key files, the Portable Symmetric Key Container (PSKC) format described in RFC6030 is supported.

The components included in the package is:

  • liboath: A shared and static C library for OATH handling.

  • oathtool: A command line tool for generating and validating OTPs.

  • pam_oath: A PAM module for pluggable login authentication for OATH.

  • libpskc: A shared and static C library for PSKC handling.

  • pskctool: A command line tool for manipulating PSKC data.

For further information, see the Documentation page.


OATH Toolkit is free software and is licenced under the terms of the LGPLv2+ (libraries) and GPLv3+ (tools).

External Resources and Applications

Here are resources that I know of, if you know of more drop me a line and I’ll add them to the list.

Please let me know if any of these links need updating.

Mailing list

Discussion around the OATH Toolkit happens on the OATH Toolkit discussion list, this keeps things transparent and gives everyone a chance to comment.