How do I make a file self-destruct?

Question

Does anyone know of an easy way to encrypt a file that deletes itself if I type in the false-password: oklahoma?

It would need to self-destruct only if I type oklahoma.

I would need it to decrypt if the correct password is entered: turtle

Any suggestions? Strong encryption preferred...

Answer 1

The data destruction tactic could be defeated if a backup copy is first made. As an alternative, you might be interested in Truecrypt's hidden volume feature. It offers two forms of plausible deniability:

1. The encrypted data appears to be random noise, and thus cannot be proven to be a truecrypt volume.
2. If you are forced into revealing your password (e.g. extortion), you could fake decryption of the volume without revealing the passkey of the hidden volume.

Answer 2

You don't. Data is data.

If you need it to handle like it's not data you need to make it not be data. People facing this have come up with a couple of schemes:

It could work like a smartcard so it's a self-contained active device that can't be read (for duplication) and you can only negotiate with the device to give you temporary access. Then you could have anti-tampering tricks in it. Self-destruction on 'oklahoma' can be done by the gatekeeper logic.

It could be on-line or otherwise in a "trusted" place, and as before you'd need to negotiate temporary access to it. This means there isn't any access to the container. You'll need someone/something that provides the gatekeeping service for you. They should also guarantee that the data is destroyed on 'oklahoma'.