Yubico provides the libraries for YubiKey OTP development and parsing. To be useful, these packages need to be combined with a database and server component.

Please note that most applications typically talk to a verification server using our client libraries.


Basic YubiKey OTP parsing libraries for C and Java, created by Yubico.

C Library: “yubico-c” project
Java Library: “yubico-j” project

Windows ActiveX/COM component*:

Windows installer
Documentation (pdf)

PAM module

The PAM module enables the use of the YubiKey for authentication in any environment that relies on the Pluggable Authentication Module (PAM) system. Useful for GNU/Linux desktop login, Solaris login, Windows login via pGina, MyProxy, SSH, and so on.

PAM: “pam-yubico”

Windows Server API*

Server support functionality for challenge-response, YubiKey OTP and OATH-HOTP validation.

User guide (pdf)
Binary installer (Digitally signed)

* Not Open Source

Windows Client COM API*

The Client API for YubiKey 2.2 and later versions, featuring support for device serial numbers and challenge-response.

User guide (pdf)
Binary installer for 32-bit / x86 (Digitally signed)
Binary installer for 64-bit / x64 (Digitally signed)