wPadlock

wPadlock adds an additional PIN field to your login page. In order to login, you’ll be using your credentials and PIN generated from your account on https://wpadlock.com

Major features in wPadlock include:

• PIN field automatically added to your login page
• You generate the PIN when you need to login (first create account at https://wpadlock.com)

PS: You’ll need an wPadlock.com API key to use it. Keys are free, but donations are welcome (free for personal and commercial use).