You missed the old standby - the microwave oven. The disk remains physically intact (at least after the 5 seconds or so I've tried), but a great deal of pretty arcing occurs in the conductive data layer. Where the arcs travel, the data layer is vapourized. The end result is an otherwise intact disk in which the data layer is broken up into small intact islands surrounded by clear channels. It might be interesting to try a longer burn, in which case you might also want to put a glass of water in with the disk(s) to preserve the microwave's electronics. This is probably less effective than the other methods you've described, but its very fast and leaves no noxious residues. It also uses a very commonly available tool. Peter Trei -----Original Message----- From: owner-cryptography@metzdowd.com [mailto:owner-cryptography@metzdowd.com] On Behalf Of Peter Gutmann Sent: Saturday, January 28, 2006 2:25 AM To: cryptography@metzdowd.com; jthorn@aei.mpg.de Subject: Re: thoughts on one time pads Jonathan Thornburg <jthorn@aei.mpg.de> writes:
Melting the CD should work... but in practice that takes a specialized "oven" (I seriously doubt my home oven gets hot enough), and is likely to produce toxic fumes, and leave behind a sticky mess (stuck to the surface of the specialized oven).
For no adequately explored reason I've tried various ways of physically destroying CDs: - Hammer on hard surface: Leaves lots of little fragments, generally still stuck together by the protective coating. - Roasting over an open fire: Produces a Salvador Dali effect until they catch fire, then huge amounts of toxic smoke ("fulfilling our carbon tax quota" was one comment) and equally toxic-looking residue. - Propane torch: Melts them without producing combustion products. - Skilsaw: Melts them together at the cutting point, rest undamaged. - Axe: Like skilsaw but without the melting effect. - Using the propane torch and hammer to try and drop-forge a crude double- density CD: Messy. Peter. --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo@metzdowd.com --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to majordomo@metzdowd.com ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE [demime 1.01d removed an attachment of type application/pgp-signature which had a name of signature.asc]