Re: [Full-Disclosure] Time Expiry Alogorithm??

From: Vincent Archer (
Date: 11/22/04

  • Next message: Curt Purdy: "RE: [ok] [Full-Disclosure] Certifications"
    Date: Mon, 22 Nov 2004 12:28:06 +0100

    On Fri, Nov 19, 2004 at 11:44:14AM -0500, wrote:
    > > For example an email message maybe decrypted withing 48 hours of its
    > > delivery otherwise it become usless or cant be decrypted with the
    > > orignal key
    > So now it's 3 weeks later, and I can't read the email...
    > So I set the date on the PC back 20 days, and now it's within 48 hours
    > of delivery. Now, what was this about "unreadable"?

    Well, you can ensure that a mail can't be read after the elapsed time.

    Encrypt it with a one-time key. Make the key available for on some kind
    of server for the allocated period, and disappear. Unless your recipient
    takes the key in time, the message can't be read.

    However, once you have read the message once, there is nothing that
    can be done to prevent the user from reading it again, even after the
    48h. Once the data is in the hand of the "ennemy", then you can't
    trust anything.

    Vincent ARCHER
    Tel : +33 (0)1 40 07 47 14
    Fax : +33 (0)1 40 07 47 27
    Deny All - 5, rue Scribe - 75009 Paris - France
    Full-Disclosure - We believe in it.

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