Full Disclosure mailing list archives
Re: Re; Time Expiry Algorithm
From: Raj Mathur <raju () linux-delhi org>
Date: Sun, 21 Nov 2004 21:10:45 +0530
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"jax" == Jacqueline Singh <jacqueline.singh () gmail com> writes:
jax> /me shakes her head at Andrew Farmer. Okay, now it's just jax> ridiculous to suggest that you wouldn't be able to implement jax> a time limitation on something encrypted simply because jax> "clocks can be changed". jax> What 'clocks' are talking about -- which are you basing it jax> off of? jax> What if you decided to code into the encryption the use of jax> atomic clocks, and include more than one or two as a jax> redundancy/security check? jax> Someone's really going create a huge conspiracy to change a jax> few of the world's atomic clocks drastically to be able to jax> crack someone's encrypted data? :P Nope, but one would happily set a policy that re-routed requests to the atomic clocks to a local system, also with flawed time, in an intermediate router. There is no way to have time-limited encryption, even under control of a remote server, since the first time the document is decrypted and rendered the client just needs to save the decrypted document. Remember Apple's Fairplay and Hymn? Similar problem -- once the decrypted data stream is available on the local PC there's no way to prevent the user from saving it in a format of her choice; unless you make a blackbox appliance, which too would get cracked eventually. Regards, - -- Raju jax> -jax >> To: "Gautam R. Singh" <gautam.singh () gmail com> Cc: >> Full-Disclosure Full-Disclosure >> <full-disclosure () lists netsys com> From: Andrew Farmer >> <andfarm () teknovis com> Subject: Re: [Full-disclosure] Time >> Expiry Alogorithm?? Date: Fri, 19 Nov 2004 10:28:20 -0800 jax> Gautam R. Singh <gautam.singh () gmail com> wrote: >> I was just wondering is there any encrytpion alogortim which >> expires with time. 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 >>> No. Think about it for a moment. >>> (Clocks can be changed.) - -- Raj Mathur raju () kandalaya org http://kandalaya.org/ GPG: 78D4 FC67 367F 40E2 0DD5 0FEF C968 D0EF CC68 D17F It is the mind that moves -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) Comment: Processed by Mailcrypt 3.5.8 <http://mailcrypt.sourceforge.net/> iD8DBQFBoLbtyWjQ78xo0X8RAhuEAJ0Zp0ENFfd61vlrs1DvESAiUMWUYwCcCpFz DFmp9llBJjGaabDfmnnX1NM= =dQSw -----END PGP SIGNATURE----- _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
Current thread:
- Re; Time Expiry Algorithm Jacqueline Singh (Nov 21)
- Re: Re; Time Expiry Algorithm Raj Mathur (Nov 21)
- Re: Re; Time Expiry Algorithm Andrew Farmer (Nov 21)