yubikey-val binary package in Ubuntu Trusty i386

 YubiKeys are USB tokens that act like keyboards and generate one-time
 passwords. This package contains a server written in PHP for use with
 Apache to validate YubiKey OTPs. The architecture is that a set of
 validation servers manage the token counters and respond to OTP requests
 from clients, and utilize a set of back-end YubiKey Key Storage
 Module (KSM) servers to perform the actual AES key decryption. The
 protocols are openly published. There are two implementations of the
 KSM available: yubikey-ksm (PHP, secrets on disk in database) and
 yhsm-yubikey-ksm (Python, for use with secrets protected by the YubiHSM
 hardware). Sometimes the KSM runs on another server than the
 validation server, but it is possible to run both on the same
 machine. After installing and configuring this package you will have
 a YubiKey validation server up and running via Apache.

Source package