Architecture of One Time Password with Voice Call from SIP to PSTN

One Time Password (OTP) is a one way authentication mechanism that usually used to verify user. Generally the media used in OTP is SMS (Short Text Messages). But besides SMS, sound can be used as an alternative media. SIP (Session Initiate Protocol) is a protocol that can send multimedia objects including sound. SIP can also be connected to a PSTN (Public Switched Telephone Network) through a media gateway. Therefore, this research focuses on building a system that can send OTP from SIP to PSTN. The result of this research is an API (Application Programming Interface) developed with the REST (Representational State Transfer) architecture. This API can send OTP audio from SIP to PSTN. Besides it, This API has also been tested to send many OTP simultaneously at the same time.