Wiping Algorithms:
Zeroes
The unused space or file is filled with zeroes through 1 pass. The fastest but the least secure algorithm. Also it does not conceal the fact that the disk or file has been wiped.
Pseudo-random numbers
The unused space or file is filled with pseudo-random numbers through 1 pass. A slower but little bit more secure algorithm than the
Zeroes algorithm and it also conceals to some degree the fact that the disk or file has been wiped.
DoD 5220.22-M(3)
The unused space or file is wiped using Department of Defense standard 5220.22-M(3). Provides high-grade data wiping filling the unused space or file with a special digital pattern through 3 passes This algorithm is very secure, but slow.
DoD 5200.28-STD(7)
The unused space or file is wiped using Department of Defense standard 5200.28-STD(7). Provides high-grade data wiping filling the unused space or file with a special digital pattern through 7 passes. This algorithm is very secure, but very slow.
Peter Gutmann (35)
The unused space or file is wiped using the Peter Gutmann's algorithm. Provides high-grade data wiping filling the unused space or file with a special digital pattern through 35 passes. This algorithm is military-level secure, but horribly slow.
What algorithm is to choose, depends on your specific needs. All of these wiping algorithms make recovery of wiped data with any software-based data recover utility impossible. So if you want to protect your information from a casual snooper, you may safely choose either the Zeroes or Pseudo-random numbers algorithm. The latter also conceals the fact that you wiped the data.
If you want more security, you need to know the following:
There are some techniques for recovery of wiped data. These techniques are based on the fact that magnetic medium on the hard drive's platters "store" some information about previously written data. Such information cannot be completely removed. Wiped data may be recovered even from mechanically damaged platters.
So the only safe way to completely remove data from a hard drive is to mechanically grind the magnetic medium off the drive platters or dissolve them in special chemical solvents.
But in order to recover the wiped data using one of these techniques, a hard drive must be disassembled, its platters placed in a precise magnetic field measurement system, and the results of such measurement statistically processed. All that is very expensive and requires a very qualified and experienced personnel and a specially developed equipment. Only a very advanced organization such as a law enforcement or intelligence agency of a developed nation, or a special high-tech firm can afford this. Moreover, each successive wiping pass makes such data recovery much and much harder. So, the DoD 5220.22-M(3) clearing and sanitizing standard overwriting the data with a special pattern through 3 passes is a rather reliable and safe choice for this case.
If you need the ultimate security, use the DoD 5220.22-M(7) clearing and sanitizing standard, or even the Peter Gutmann (35
) wiping algorithm. They render data almost unrecoverable, but they are extremely slow
ایا اطلاعات شما با deletکردن پاک میشه ؟
.gif "N Aggressive (39)")
.gif "N Aggressive (25)")
.gif "N Aggressive (17)")
.gif "N Aggressive (16)")
جواب بصورت نقل قول
نوشته شده توسط itpro
