Near sound data transfer

Near Sound Data Transfer (NSDT) is a sound-based mobile transaction technology developed and patented by Tagattitude since 2005. NSDT uses a one time password sent through the audio channel of a mobile device to create an electronic signature enabling secure transactions. The technology uses a phone's audio input and output (speaker and microphone) functionality and thus is compatible with mobile phones in use worldwide.

Applications
NSDT is primarily used for mobile banking transactions through the mobile money platform Tagpay. It is also used to securely open doors and enable authentication on websites.