In episodes of “Mission: Impossible,” a voice explains a new assignment to the hero, then warns that the message "will self-destruct in five seconds."

Now, iPhone users can make their emails, text messages, photos and videos do the same with a new security app.

Wickr, a free app made available Wednesday in Apple's App store, encrypts communication, allows users to remain anonymous and gives senders control over who reads their messages, where they read them and how long they can read them for (one second to five days) before they're permanently deleted.

Currently, when users delete data from their phones, it is not gone forever. It still resides on the phone's internal memory or on a server belonging to a company, which is free to sell the data to advertisers and is under no obligation to keep it secure using encryption, according to Robert Statica, a co-founder of Wickr.

Statica, who is also a professor at New Jersey Institute of Technology, said his students have bought smartphones on eBay and retrieved sensitive communication from the phones' hard drive, even though the previous owners thought they permanently deleted the data.

"From credit cards to bank statements, you name it. We recovered everything," he said. "It's just like a hard drive on a computer. When you delete a file, it doesn't actually get deleted. Using forensic software you can recover files very easily."

Wickr, Statica said, uses technology to ensure that messages cannot be recovered, not even by law enforcement officers, who can acquire subpoenas to compel wireless providers or Internet service providers to turn over suspects' data as evidence.

The app may be valuable not just for those worried about the police, its creators say, but also for doctors, lawyers or stock traders who may be concerned that confidential information could fall into the wrong hands if their phones are lost or hacked.

Nico Sell, another co-founder, said Wickr is also meant for anyone who feels uncomfortable with the idea that companies can make a profit by selling users' personal data to advertisers.

"We think communications should be untraceable," Sell said. "Everything about you is worth money and we're just giving it away for free."

The app is currently free, but Wickr's creators are planning to launch a premium edition that allows users to send larger files, share them with more users and store them indefinitely.

The app does not completely prevent sensitive data from being saved, however. The New York Times notes that a recipient of a message could take a screenshot of it and store the information before it self-destructs.

Wickr's creators are not the first to come up with a program to destroy digital messages for security purposes. In 2009, computer scientists at the University of Washington developed a software called Vanish that makes emails disappear.

And in 2007, a small email provider called BigString created a service in which messages could be timed to self-destruct.