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NAMEwipe - secure file deletion utilitySYNOPSISwipe[-ucwsiIhfFdDnNvVzZrRtTkKaAeE] [-B(count)] [-S(size)] [-C(size)] [-o[size] -O] [-l[0-2]] [-x[1-32] -X] [-p(1-32)] [-b(0-255)] [files] DEFAULTwipe -ZdNTVEAkO -S512 -C4096 -l1 -x1 -p1DESCRIPTIONWipe is a secure file wiping utility. There are some low level issues that must be taken into consideration. One of these is that there must be some sort of write barrier between passes. Wipe uses fdatasync(2) (or fsync(2)) as a write barrier, or if fsync(2) isn't available, the file is opened with the O_DSYNC or O_SYNC flag. For wipe to be effective, each pass must be completely written. To ensure this, the drive must support some form of a write barrier, write cache flush, or write cache disabling. SCSI supports ordered command tags, has a force media access bit for commands, and write cache can be disable on mode page 8. IDE/ATA drives support write cache flushes and write cache disabling. Unfortunetly, not all drives actually disable write cache when asked to. Those drives are broken. Write caching should always be disabled, unless your system is battery backed and always powers down cleanly.Under linux, the mount option "mand" must be used (see linux/Documentation/mandatory.txt) for mandatory file locks to be enabled. Wipe should make it extremely difficult for all but the most determined person(s) to recover the original plaintext data. Utilities such as PGP and the GNU Privacy Guard provide strong encryption, but encryption is useless if the original plaintext can be recovered. When using PGP and GPG, temporary files that are disk-backed should be stored on an encrypted file system. That way, the plaintext never hits the platters. Wipe is designed for situations where an encrypted file system isn't practical. Wipe uses /dev/urandom, or if unavailable, /dev/random, as a source for entropy. The Mersenne Twister PRNG is used for speed. The MT site is at: http://www.math.keio.ac.jp/~matumoto/emt.html For more information on the secure deletion of magnetic media and solid state storage devices (such as DRAM) see the USENIX article by Peter Gutmann at: http://www.cs.auckland.ac.nz/~pgut001/secure_del.html OPTIONS
FILES
DIAGNOSTICSIf an error occurs, the exit code will be the errno value. An exit code of 2 indicates bad usage.BUGSWipe does not work on log structured file systems, or any other type of file system or block device that reallocates sectors on write.Some programs are vulnerable to symlink races. To avoid this problem with wipe, only wipe files in directories that are not writable by untrusted users. NOTESTapes and other sequential access devicesChoose an appropriate buffer size to match the logic or physical block size of the device. When using the pattern passes, you should disable compression on the drive, and it's generally best to so for other passes as well. For VXA drives, I used mt-st under linux to set the block size to 0 (variable) and turn off compression, and I run wipe with a 64k block size, to match the on-tape format''s native block size. Example: mt-st setblk 0 mt-st compression 0 wipe -C64 /dev/st0 ALTERNATIVESOther file wiping utilities:Another "wipe" by Berke Durak <durakb@crit2.univ-montp2.fr> Colin Plumb's <colin@nyx.net> sterilize. Todd Burgess's <tburgess@eddie.cis.uoguelph.ca> srm is available on sunsite/metalab in ftp://metalab.unc.edu/pub/Linux/system/filesystems/ SEE ALSO/usr/local/share/doc/wipe/READMEAUTHORSWipeCopyright (C) 1998-2009 Thomas M. Vier, Jr. <nester@users.sf.net> Mersenne Twister PRNG module
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