6 expanded posts ยท every known parent and child
Just for your information, I _WAS_ mistaken. The papers burned really well. My confusion about burnability of papers arose because in the past I tried to burn magazines, and not papers and letters. The whole big box is gone, after two burns. Burning is unquestionably better than shredding. - Igor.
At 12:19 PM 1/25/98 -0600, Igor Chudov @ home wrote: >Just for your information, I _WAS_ mistaken. The papers burned really >well. My confusion about burnability of papers arose because in the >past I tried to burn magazines, and not papers and letters. The whole >big box is gone, after two burns. Burning is unquestionably better than >shredding. There are shredders, and then there are shredders. The SOHO-sized shredders that just cut things into ribbons aren't very thorough (and it's been demonstrated that documents shredded that way can be reassembled by sufficiently large numbers of Iranian college students) but they're good prep for burning the papers. On the other hand, the cross-cut shredders that leave flakes no more than 1/8" rectangles or even smaller chad are good enough for classified documents. Of course, if your documents are on floppy disks, any shredder that won't jam on them does a pretty good job :-) Thanks! Bill Bill Stewart, bill.stewart@pobox.com PGP Fingerprint D454 E202 CBC8 40BF 3C85 B884 0ABE 4639
Bill Stewart wrote: > Of course, if your documents are on floppy disks, any shredder that > won't jam on them does a pretty good job :-) I burned a couple of floppies, too. Actually I am not sure how good job would shredding of floppies do. I assume that bits and pieces of data can still be recovered... But hopefully no one would care enough. - Igor.
[These messages were postponed for trillions of years I finally sent them;
apologies if something is grossly outdated.]
Been thinking, most applications for ciphers assume solely based on cipher x's
keysize that data will be secure for a certain length of time. It'd be nice if
we had some way to estimate how long we can hope the cipher to last. Of course,
there's no way to predict anything for sure, but you could make an estimate.
I'm wondering if there's any way to make a more accurate prediction of how much
more analysis it will survive with fancy statistics or something. My idea --
which I know wouldn't work very well, which is why I'm asking if there's a way
to actually make a good guess -- is averaging the remaining lifetimes in
analysis-hours of broken ciphers which survived as many person-hours of attack
as the one in question.
===============================================================================
Am I just going crazy, or is it kind of obvious that NSA knew the s-boxes they
provided for DES weren't secure? I mean, they pretty much had to know about the
attacks outside cryptographers are just now discovering -- they have more than
ten years of cryptographers' time every day, and they certainly knew about
differential cryptanalysis. Let's hope they don't meddle similarly in AES...
===============================================================================
> > Of course, if your documents are on floppy disks, any shredder that
> > won't jam on them does a pretty good job :-)
>
> I burned a couple of floppies, too. Actually I am not sure how good job
> would shredding of floppies do. I assume that bits and pieces of data
> can still be recovered... But hopefully no one would care enough.
One fairly simple feature for disk encryptors that came up during one of the
#ElectronicFrontiers (sp?) chats was that of using random numbers with the key
so you can demolish an encrypted volume in a split-second. Works like this:
there's one 192-bit (or whatever your keylength is) value which is a hash of
your passphrase. There's another value, this one a cryptographically random one
of the same size, stored on a fixed physical place on the disk. If you wish to
destroy the data on powerdown, there can be a third value stored in memory,
which is written to disk at authorized shutdown and read+wiped from disk at
startup.
Anyhow, these two (or three) values are XORed together to form the key used to
encrypt the volume. When your adversaries, armed with their trusty rubber
hoses, come knocking at and/or down your door, you hit a hotkey to start
destroying those 24 bytes on disk, which can be done faster and more
effectively than a wipe of every sector in the volume. The folks with the
rubber hoses are now, assuming this is their first peek at your disk, screwed;
even with your passphrase, they don't know a thing about your data.
>
> - Igor.
---------------------------------------------------------------------------
Randall Farmer
rfarmer@hiwaay.net
http://hiwaay.net/~rfarmerIgor Chudov @ home wrote: > I burned a couple of floppies, too. Actually I am not sure how good job > would shredding of floppies do. I assume that bits and pieces of data > can still be recovered... But hopefully no one would care enough. I've heard that you can look at it under a microscope with a polarizing filter and see the magnetic patterns. But it's much easier to just encrypt the disk so you don't waste the media when you're finished. Plastic should burn fine, as most is polyethylene (CH2) which produces water and carbon dioxide when burned, leaving virtually no residue. The only plastic that you'd need to worry about is chlorinated stuff like PVC.
On Sun, Jan 25, 1998 at 11:56:20AM -0800, Bill Stewart wrote: > At 12:19 PM 1/25/98 -0600, Igor Chudov @ home wrote: > >Just for your information, I _WAS_ mistaken. The papers burned really > >well. My confusion about burnability of papers arose because in the > >past I tried to burn magazines, and not papers and letters. The whole > >big box is gone, after two burns. Burning is unquestionably better than > >shredding. > > There are shredders, and then there are shredders. The SOHO-sized > shredders that just cut things into ribbons aren't very thorough > (and it's been demonstrated that documents shredded that way can > be reassembled by sufficiently large numbers of Iranian college students) > but they're good prep for burning the papers. > On the other hand, the cross-cut shredders that leave flakes no more > than 1/8" rectangles or even smaller chad are good enough for > classified documents. Maybe some classified documents. Certainly not for some others. -- Kent Crispin, PAB Chair "No reason to get excited", kent@songbird.com the thief he kindly spoke... PGP fingerprint: B1 8B 72 ED 55 21 5E 44 61 F4 58 0F 72 10 65 55 http://songbird.com/kent/pgp_key.html