Last week, several people received calls from a person who identified himself as the chief minister of Bengal, Buddhadeb Bhattacharya, asking for votes.

The number displayed was +91 1166040600. The receivers were mystified because when they tried to call back, it said: “no such number exists”. How was that possible?

In the pre-mobile phone era, when crank callers harassed women and young girls, one had to request the telecom department for the caller ID. It was a complicated process, involving making a general diary with the police and giving explicit reasons for such a request.

Mobile phones changed all that. With the caller’s number being displayed, one had the option of taking or not taking the call. If it was a crank call, one could always threaten to give the number to the police and the harassment would stop.

Last week’s phenomenon, however, showed that even with mobile phones, one is exposed to all sorts of calls. But the question is: how is that possible? Well, it’s thanks to a new tweak called Caller ID Spoofing.

It’s not only crank callers or those with evil intent who would want their phone numbers to be masked — all of us may need to do it at some point or the other to protect our privacy. It can keep us from showing our phone numbers to everyone we call.

This is a credible reason for wanting to use Caller ID Spoofing. With this, you can change your caller ID to any number you want. You can even disguise your voice and record the call. What is the easiest way to escape from being caught if you are cheating on your spouse? Use this caller ID changer to make any number you want to show up on a caller ID list.

One can even change one’s voice during a phone call on an iPhone. This new tweak, called VoiceChange, is available in Cydia, which allows you to change your voice in real time during a phone call. This tweak has to be installed on a “jail-broken” iPhone. When a call is made, this app will route the call through a remote server using an international number. Cydia is an application that allows you to add other applications to your iPhone or iPod touch.

Another popular app is SpoofApp. Its purpose, as I mentioned, is to disguise your phone number with someone else’s. And if you’d like, disguise your voice too. Yes, this means you can play a prank on anyone you’d like. And no, you can’t be traced.

Before you can make any calls, go to Settings. Enter SpoofCard as your provider. Here’s the catch. You need a Pin Number. How do you get that? You must buy minutes from “SpoofCard”.

Many of you may not know what a jail-broken iPhone is. Through a very simple procedure, it frees you from buying apps only from Apple’s iTunes store. Cydia has lots of very interesting apps, but once you jail-break your phone, you lose the warranty. Second, you have to “un jail-break” the phone whenever Apple releases updates.

So how does one trace a spoofed call? In terms of location and number (say you use an ID blocker or are calling from a public phone), the police can track the origin of the call. But they will do so only in investigations, because it takes special GPS instruments. Also, it costs precious time that the department would rather use in more “serious” crimes. And they would only act through a court order.

But to trace the calls made in the chief minister’s name, a lot of rules would surely be waived.

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