In addition, sKyWIper may have been active for as long as five to eight years, or even more. sKyWIper uses compression and encryptiontechniques to encode its files.
Ministers say they are also looking at ways that GCHQ's "world class expertise" in the area might be used to help businesses - for example looking at whether encryptiontechniques and other expertise that is not considered top secret might have commercial applications.
Many observers have suggested defensive techniques that deploy TrueCrypt disk encryption with hidden volume partitions or PGP Whole Disk Encryption rendering the entire computer unbootable thereby making even file time and date stamps unavailable.