"IB has written to DoT around a month back to block WePhone application which is freely available on Google Play Store and Apple's application store as it allows user to spoof call," an official source said.
'WePhone' application, which offers call service similar to Skype, allows user to make free calls using mobile internet service to other subscriber having same application. The application after verifying user's phone number at the time of installation gives an option to disable the number to hide it.
IB has told DoT that in free version of this application caller ID on receiver screen starts with +1777 where as in paid version any number can be set to display as caller id.
The Intelligence agency has written that the server of WePhone is located outside India and any call made from WePhone is routed through the server located abroad and therefore it is difficult to identify and locate the actual calling number or user.