Obama's India visit: Barack Obama is the most tech-savvy US President till date

The most tech-savvy US president to date, Barack Obama uses a BlackBerry in and outside of the White House

1) For the world's most powerful man, security is a lot more than having a passcode; it also means protecting his phone from amateur and professional hackers, and more importantly spy agencies, who want to know to whom, when, what and where he has been speaking and reading.

2) Obama has been an affirmed BlackBerry user for at least a decade, but after becoming president in 2008 he had to give it up briefly for a secure Sectera Edge phone specially created by the National Security Agency (NSA).But that was quickly replaced by a customized BlackBerry with special security software called SecureVoice, developed in conjunction with the NSA.

3) The new BlackBerry was stripped of every built-in feature that a hacker might exploit. It has no games, and likely no selfie-camera or texting function but carries top-notch encryption features.

4 )The phone is limited to calling only about 10 numbers, since they belong to those whose phones use the same type of encryption. They include vice-president Joe Biden, Obama's chief of staff and some of his top advisers, his press secretary, first lady Michelle Obama and a few other family members.

5 )Sources say the presidential BlackBerry can only connect to a secure base station, which can be used to hide the IMEI-number of the device and thus prevent tracking it. This means the White House Communications Agency has to carry such a secure base station wherever the president goes.

6 )There must be a secure base station inside the presidential limousine too and probably also in Air Force One. The secure base station is probably connected to a secure satellite link with Washington.