Techniques are disclosed for authenticating users to a computing application. A mobile or tablet device is used to generate a security code. Near field communication (NFC) hardware on the mobile device is used to transfer the security code from the mobile device to a computer. To transfer the one-time value, a user simply taps an NFC enabled mobile device on an NFC enabled computing device (e.g. a laptop running a web browser used to access a web service). In one embodiment, doing so triggers a connection between the two devices and an application running on the mobile device transfers the security code to an NFC receiver application running on the computer. The receiving computer may be configured to auto-fill the received security code in the appropriate form field of the application authentication interface.