The Perfect Paper Passwords plugin by Henrik.Schack for WordPress gives you free multifactor authentication for your WordPress blog.
The multifactor authentication requirement can be enabled on a per user basis, You could enable it for your administrator account, but login as usual with less privileged accounts.
The Perfect Paper Passwords system was created by Steve Gibson, https://www.grc.com/ppp
This plugin requires the SHA256 hashing algorithm, the BCMath library and Mcrypt/AES-128 (Rijndael-128) to be available in your website’s PHP installation.
Download and info: http://wordpress.org/extend/plugins/perfect-paper-passwords/
