Messages in this thread | | | Subject | Re: Unswappable memory needed is user space | Date | Tue, 08 Dec 1998 09:23:04 -0800 | From | "Zow" Terry Brugger <> |
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> I'm making a crypto program (under french law). > It crypts a file and then totally erase the uncrypted by filling it with > zero. > Don't know about the non-swap mem, but what you're doing here is another problem. Just writting zeros to the disk won't prevent the file from still being read off the disk by some very syphisicated techniques (done by looking at the magnetic fields on the platter in a clean box). Instead, you want to write over the file at least three times with random bits. This too may be insufficient if ext2 (or whatever other underlying fs) relocates the file when you go to write over it (hence, the origional is in one place, marked as free space, and your random data is in another). Anyone know more about this? > > christophe leroy > -"Zow"
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