The increasing use of an exclusive and underground Voice-over-Internet Protocol (VoIP) application by suspected terrorists has sent alarm bells ringing among the Indian security establishment which believes it to be a creation of the Pakistani spy agency ISI.
The clandestine, Skype-like application being used by suspected terrorists is hosted on anonymous servers, hidden behind security walls, that operate underground and cannot be intercepted through legal means.
"The only way to intercept these conversations is to hack them, but they are highly secured due to high grade encryption. We are finding it difficult to crack it," said a security official.
The recent annual meeting of the Directors General of Police (DGPs) was told that this anonymous platform was probably developed by the ISI for communication between terror outfit Lashkar-e-Taiba (LeT) cadres and their handlers. The access to platform is restricted to those who have been allotted a login and password, according to officials familiar with the developments.
Terrorists often communicate over internet-based platforms, intercepting which has been part of anti-terror interventions.
The 26/11 Mumbai attack was first major operation where the 10 member LeT attack squad effectively used VoIP to remain in touch with their handlers sitting in Karachi.
Indian Mujahideen's top operative Yasin Bhatkal, while sitting in Nepal, was using VoIP platforms to contact his associate Riyaz Bhatkal, who is in Karachi, Pakistan.
The ISI developed VoIP service has been in use for more than a year.
"There are software available to develop private and exclusive VoIP service. It is quite possible that the ISI may have tweaked the software to suit its requirements. Such kind of service is always distributed on many servers and kept anonymous. Usually security layers of VPN or virtual private network and proxy tunnels are used as an additional security," says Dhruv Soi, director of Torrid Networks, a cyber security company.