We've seen it in movies like Mission Impossible: the message that self-destructs in 30 seconds. Wouldn't it be nice to have something like that for email, too?

Enter Dmail, the Chrome browser add-on you can use to set emails to destroy themselves within a set time period of your choosing.

Dmail is for those times when you're sending sensitive information meant for certain eyes only. It's for those emails with important messages that won't be saved later and won't be turned up by a hacker and submitted to the public, similar to what recently happened with Sony.

Dmail takes the concept of Google's current un-send feature a step farther. You can set up a period of time that an email remains active and then have it destroy itself so that no one else can ever see it. And soon, Dmail will even let you set an email so that it can't be forwarded to others.

Dmail, which comes courtesy of the team behind bookmarking service Delicious, works like this: You install a Google Chrome web browser extension. Then, once you start composing an email in Gmail, you get a new option to turn Dmail on or off. When it's on, you can set the time you want the email to destroy itself. Or you can set the email to never destroy itself (although you can change your mind later and revoke email messages to those who receive them).

The person receiving the email doesn't need Dmail for the features to work from your end, although if they also have the extension installed in their browser, they have the liberty of viewing the email directly in Gmail (otherwise, they receive an email with a link where they can view your message). Once the message self-destructs, recipients get a message that the email is no longer available when they try to read it.

If you're worried about security, don't be: each message sent through Gmail with Dmail becomes encrypted.

"An encrypted copy of that email is sent to a datastore controlled by Dmail," said Dmail product lead Eric Kuhn to TechCrunch. "The recipient of the email is sent both the location of that datastore, as well as a key to view the decrypted message. Neither Gmail nor Dmail servers ever receive both the decryption key and encrypted message. Only the recipient and sender can read the email legibly."

Dmail only works with Gmail now, but it's likely to expand to work with other services soon, with plans to release both an iOS and Android version this fall.