	MCSoft Security Solutions

Product Overview

Software

MCWipe

Algorithms

MCSoft MCWipe

Wipe Functions in MCWipe - Preventing the recovery of files and folders

The following Wipe Functions can be applied:

Quick Wipe:
One time overwriten method of the file with zeros. No repetition possible. Fastest method.

Full Wipe:
The file is overwritten with random values three times. Possible are up to ten repetitions.

1. Run: overwrite the data with pseudo random values
2. Run: overwrite the data with the complement value of the first run
3. Run: overwrite the data with pseudo random values

U.S. Standard, DoD 5220.22-M (E):
A standard was developed by the Defence Security Service (DSS) which should solve the problem of the permanent removal of data for some time. This was used by many commercial enterprises. Under the National Industrial Security Program (NISP) representatives of the Industrial Security presented their security programs. As a part of these NISP the DSS developed the DoD 5220.22-M standard (National Industrial Security Program Operating Manual - NISPOM). Which is used in the meantime in almost every deletion tool.
In this manual is beside other procedures the description of a method for the removal of data from magnetic media. The NISP defines a technique for the overwriting of data so that all information is removed from the medium. This wipe algorithm uses three write runs:

1. Run: overwrite the data with a defined fixed value
2. Run: overwrite the data with the complement value of the first run
3. Run: overwrite the data with pseudo random values

In the regulations of the US American Ministry of Defense people refer expressly to the deletion of information on media with the military classification "Secret" or "TOP-Secret" which is not allowed with this method. For the home use this method is, however, surely sufficient. It is possible to use up to ten repetitions.

U.S. Standard, DoD 5220.22-M (ECE):
This method is an extended variant of the DoD 5220.22-M. This variant of the DoD Standard uses for overwriting the data seven runs. Here the data is overwritten two times by using the DoD 5220.22-M (E) standard and one time with random value DoD 5220.22-M (C). It is possible to use up to ten repetitions. The sequence of the runs is the following:

1. to 3. run: overwrite the data with the DoD 5220.22-M (E) Standard
4. run: overwrite the data with pseudo random values, the DoD 5220.22-M (C) Standard
5. to 7. run: overwrite the data with the DoD 5220.22-M (E) Standard

Peter Gutmann:
Peter Gutmann presents in his 1996 published work (Secure Deletion of Data from Magnetic and Solid-State Memory) a method for the deletion of different media types. The procedure developed by Peter Gutmann includes also coding patterns which are used for the coding of the medium by the hard disk manufacturers. In this case all permutations of four-digit bit patterns that can be used for the data storage on the hard disk are written after each other in overall 35 individual runs. As a consequence on magnetical media the remanence of the original data is so grainy, that a reconstruction of the data is impossible. In this way the method is because of the use of many runs very time-consuming, but it is regarded as extremely secure. It is possible to use up to ten repetitions

Overwriting Data by using the ISAAC CSPRNG
The most secure and most complicated method for the deletion of data on magnetic media is to overwrite the data with a CSPRNG (cryptographically secure pseudo random number generator) . With 36 runs this method offers a secure and reliable protection against attacks also on modern magnetic media. Even for intelligence services it is most probably not possible to reconstruct any useful data. This method is very time-consuming. It is possible to use up to ten repetitions.