does anyone know of an encryption that can only be deciphered with a key during a certain period of time (say you specify 6/12/2002 -> 6/17/2002 (us date format) )?

If anyone knows if this is possible?

Posted on 2002-06-06 18:04:54 by Hiroshimator
Well... what would prevent a potential cracker from setting the date on his computer to within that range even if it's taken him a year or so?

So no I don't think that's at all practical...
Posted on 2002-06-06 18:40:15 by AmkG


Posted on 2002-06-06 20:04:05 by ancev
have it check a time server for correcxt time?????
Posted on 2002-06-07 02:10:09 by Qages
then you can forge the reply :/
Posted on 2002-06-07 04:44:55 by Hiroshimator
then you can forge the reply :/

Maybe have a key server that sends a hash of the current time wich is used in decryption
Posted on 2002-06-07 05:38:12 by Kudos
Part of the problem is whether the encrypted data can be retrieved before the time window, and whether it would be worth keeping after the time window.

Point is, if the answers to the above questions are positive, you face the problem of copied keys.

If the data is static, you can use a variable key, and a variable time-hash from a server to decrypt. This results in the problem of "once decrypted easily copied", but has the advantage of no copied keys (they'd be useless, unless you also copied the time-hash, and forced the program to accept that time-hash).

If the data is dynamic, you can have a static key, and a time-hash. This way you can copy the key, but the key itself would be useless without a time-hash and the right data (so don't use the key to authenticate downloads).

Just a suggestion.

Posted on 2002-06-07 08:29:37 by Fake51