Authentication is a critical process for any IT system, from website to ERP-system. Single Factor authentication is not of this age anymore. Multifactor is the way to go. One way to add factors is One Time Password systems. The Yubikey is such a system. It consists of a hardware OTP-key and a server back-end, either at Yubico, or self hosted. You can order the key and download additional software at Yubico:

Here’s what this is all about (copied from the Yubico Site):

Secure - The YubiKey combats common ID theft issues including phishing, key loggers and other means of eavesdropping. For two-factor authentication, the device can be combined with a PIN or password.

Easy - Identification and authentication is performed in seconds without the hassle and risk of error when typing long pass codes from an authentication device onto a computer. It works with legacy login and on all computers, platforms and browsers with no client software needed. (Windows, Linux, Mac, Internet Explorer, Firefox, etc.) Quick and easy integration into any application.

Portable – Easy to move between computers. Easy to carry with you, in your wallet or on your keychain.

Open source – Our business is to sell the unique and patents-pending hardware. We provide a basic validation service and the server components for free and as open source.

Multiple use – Yubico supports open identity standards (SAML, OpenID, etc.) and provides a free validation service enabling one YubiKey to be used for multiple applications. Optionally, users can program the YubiKey to have two independent and separate configurations, including any two of the three alternatives:
Standard YubiKey 44 character one time pass code.
OATH 6 or 8 digit one time password
1-44 character static pass code

Green - The robust, hermetically sealed, ultra-thin and battery-free design with no moving parts increases lifetime and reduces environmental impact.

Brandable - in volume, the YubiKey is supplied in a form that enables screen printing or laser etching of branded logos and messages.

Cost-efficient – Unmatched price point due to minimum manufacturing and transportation cost, no battery support, open source server components and web based sales.

An example of ways to use a Yubikey is shown in the video below: