116 her client, Tata. Not surprisingly, Radia's Idea and MTNL numbers only were intercepted. Anil Ambani's aide Tony Jesudasan uses only Reliance cellphone numbers. Sources say both the it Department and CBI wanted to tap Jesudasan's number but decided against it for obvious reasons. Singh had a friend in Vodafone's senior management who warned him of all his four numbers being monitored by the Delhi Police, thus giving him time to destroy incriminating evidence. There is a twist in this tale. A majority of surveillance equipment was acquired to keep track of organised crime and terrorism. Intelligence agencies rue that phone tapping and interceptions are now yielding diminishing returns because terrorists have found new ways of staying ahead of them. Terrorists are increasingly using BlackBerry phones while their handlers are using the new generation Inmarsat-4 satellite phones, making their interception next to impossible, at least for now. Though Inmarsat-4 phones can be monitored off the air, the conversation is available only in encrypted format. Voice and data can be effectively monitored only at the Inmarsat-4 switch in London and New York, where it is available in decrypted form. That is the reason why India still has to depend upon British or US intelligence agencies for information. Voice over Internet Telephony (voip)-based Skype and Google mail and chat are also extensively used by terrorists, small-time criminals and corporate houses. Free software can be downloaded on smart handsets and computers to encrypt calls and mails. Commercially available software like Cellcrypt has been found to be most effective in securing conversations and messages. Compatible with all smartphones, Cellcrypt aids in personalised encryption of all communication. The only catch for completely secure communication is that handsets at both ends should have the software. If only one of the handsets has installed the software, the communication will be available in decrypted format at the other end.