If you've seen Mission Impossible, you may remember how Tom Cruise receives mail with the instruction, "This mail will self-destruct in ..." Now don't be surprised if you get self-destructing mail, at least e-mail.

A unique product can send an e-mail with a self-destruct capability that can be set by the sender. This makes the e-mail impossible to read after as little as a few seconds or minutes, depending on the settings. The name of the company behind this software -- you've guessed it -- is Disappearing Inc.

The system encrypts each message with an electronic key held by both the sender and the receiver. The sender can decide how long the key will work -- from a few seconds to years -- after which the key self-destructs and the message becomes unreadable. A complete audit trail is maintained for each message, indicating who has received the message and when they first read it. The system works within a company's existing e-mail system on existing servers.

When a message is deleted, all copies – including those stored on back-up tapes or forwarded to third parties – become unreadable. This eliminates the devastating liability created by casual comments archived permanently in e-mail. This system operates seamlessly with leading security solutions and also offers an alternative security solution for dealing with people who have not registered with a certificate authority.

This system can prevent the wrong people reading an e-mail after the receiver has opened it. The e-mail is, in any case is unprotected, besides the fact that it could be from "anonymised" sources like www.anonymizer.com.

The sender may continue to be anxious to know if the receiver has got the e-mail and read it. With normal e-mail, there is no feedback about who reads your message and when. Though some systems offer return receipt, these don’t work across different e-mail systems. Another hassle with normal e-mail is that copies hang on in directories, on back-up tapes, off-line machines, on recipients’ machines, as forwarded messages, and so on, and stand up as crucial evidence in corporate litigation.

Most other e-mail security systems focus on authenticating an individual and then granting him access to all of their documents but Disappearing Inc.’s software allows companies to not only authenticate users but also track and delete individual documents. Other tracking systems don’t work across different platforms -- like Netscape Mail and Microsoft Outlook, for example.

It has been estimated in market studies that by the year 2002, more than 60 per cent of companies adopting e-commerce will use Internet management and security tools like Disappearing Inc.'s.

This product should be available early next year, according to the company. It is in the pre-release stage now and is aimed at high-tech, financial services, e-commerce and telecommunications companies.

But just think of the possibilities, good and bad. E-mails have now turned up to be treated as legal evidence -- ranging from Bill Gates' threats against Microsoft's rivals to US congressional investigations into Monicagate and the Iran-Contra affair. The problem with e-mail is that it can reach the wrong persons, and there is no way to recall an impulsive bout of emotional outpouring. Disappearing's act could restore some of the balance to the harassed sender in such cases, but there is no end to the kind of harm that can come out of it. Just wait and see.