On Thu, 2 Jul 2009 16:49:24 -0500, Tom Harper wrote: >Gerhard, > >According to this source, that theory [track edge residue] >is in question: > >http://www.h-online.com/security/Secure-deletion-a-single-overwrite-will-do-it--/news/112432 > >(watch the wrap). > Thanks. I long wondered, given that disk technology is pushing the physical limits, how one might expect to do orders of magnitude better -- if one can recover the original data, one must be able similarly to recover the content of each intervening random overwrite pattern.
The cited article and its followups point out that it's a greater concern to erase all temporary copies of the file (how often do you S(ave) during an E(dit) session?) And that this concern is magnified in RAID systems which intrinsically keep redundant data. I searched Google for "ZFS SECURE DELETE", since Time Slider's ability to recover deleted files exaggerates the hazard. The consensus is that ZFS has yet no secure delete facility; an alternative is to keep the data encrypted and destroy the key. (How do you assure that all errant copies of the key are destroyed? Same way you assure that all errant copies of the base data (on laptops, SD cards, etc.) are destroyed.) -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
