Meet the world's most secure smartphones (in pictures)

A phone with real promise, created by aerospace and defense giant Boeing. The so-called "Black" smartphone (not to be confused with the Blackphone) comes with trusted data transmission for connections to both classified and unclassified networks, which in part led to the device being approved for Dept. of Defense use. The Android-based phone, once described as providing a "Fort Knox-like level" of data security, costs about $629. But don't tamper with it, or the phone will self-destruct -- seriously (but don't worry about it fizzing in your pocket).

Used personally by the French president, the Teorem smartphone, built by the Thales Group, protects both calls and text messages. The flip-phone works on both 2G and 3G networks, and comes with a notification light to tell the user when a call is secure. And the phone itself is designed to be tamper-proof. The phone can also be docked and used as a desk phone, if required.

Despite being the world's first unlocked, dual-SIM smartphone that comes with the Tor anonymity network preinstalled, the BOSS Phone might not ever make it to market. That's because the crowdsourcing effort to get it off the starting block has stalled. The Android-based phone promises to include Tor as standard, which anonymizes and scrambles web traffic. It will come with device encryption, which comes as standard in Android Lollipop (though, it isn't switched on by default in most non-Nexus devices.)

Another phone that has promise ahead of its formal launch to market, the Turing Phone promises to offer "total protection" from hackers. While no phone (or any device for that matter) is entirely hacker-proof, this phone takes a good stab at it. Its trick? A hardware chip, dubbed the Turing Imitation Key, that authenticates encryption locally rather than relying on a server to issue a certificate. The phone runs the latest Android Lollipop software, which includes device encryption.

US-based cellular company FreedomPop built its own anti-hacker and privacy-centric smartphone based on Samsung hardware (the device itself is a Galaxy S2, but its tricks are mostly software-based) and Android software. The phone allows you to anonymously browse the internet, and offers 128-bit encryption for texting and calling. And, if you want to buy the device anonymously, you can do so in bitcoin.

US President Barack Obama wanted to keep his BlackBerry -- for good reasons. It was for a time (and remains) one of the most secure way of emailing people, thanks to its encrypted and decentralized email service. Obama was slated to use a Sectéra Edge, but managed to win over the Secret Service to let him use a beefed-up BlackBerry. Obama's phone comes with a SecureVoice addition, toughened further by the NSA.

Sectéra Edge may not win awards for how it looks, but it's said to be one of the most secure devices for private industry and government users. The device, built by General Dynamics, is certified by the NSA and eligible for use on government networks. Most of the devices in use run a variant of Windows. The PDA-style keyboard-enabled smartphone costs more than $3,000 per device, and is widely used in the Dept. of Defense and Homeland Security.