Security for VOIP


Voice over IP (VoIP), the use of the packet switched internet for telephony, has grown substantially in the past ten years. Securing VoIP has many challenges that do not exist in the public switched telephone network (PSTN), a circuit switched system. VoIP is an application running on the internet, and therefore inherits the Internet security issues. It is important to realise that VoIP is a relatively young technology, and with any new technology, security typically improves with maturation.

Hackers will attempt to get into these new services but they’ll start where they can find the most lucrative or high profile challenge. If small businesses and individuals take normal sensible precautions there is no reason to believe that VoIP will create any new or increased threat.

How It Works:

For Security we need TLS protocol and also required  certificates. On both the side device and server needs to validate certificate. Kamailio server is required. Transport configuration settings needs to handle with TLS protocol. Many configuration and installation needs to done with open ssl and  some shell script file.


If you want to implement security features over this library then above code is the right way to go. But for this to work you will need 3 types of certificates

Now these files are necessary to obtain encryption.

     1. CA certificate

     2. Server Certificate (SSL certificate)

     3. Private key to open the server certificate.

Please use the following lines to configure SRTP.

    cfg.use_srtp = PJMEDIA_SRTP_MANDATORY;

    cfg.srtp_secure_signaling = 1;

This config defines the use of SRTP is mandatory and signaling is achieved by TLS.

This document will get you ready to build a basic app with secure features.


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