Net Zeros and Ones

CHAPTER 3Data Sanitization Technology

• 3.1 Shredding
• 3.2 Degaussing
• 3.3 Overwriting
• 3.4 Crypto-Erase
• 3.5 Erasing Solid-State Drives
• 3.6 Bad Blocks
• 3.7 Data Forensics
• 3.8 Summary

There are as many ways to destroy data as there are to store it. All data should be accounted for in a plan of data lifecycle management. Paper records should be stored and accessible for easy retrieval in case a legal discovery process is kicked off. But after their useful and legal life, they should be destroyed in an ecologically sound way. This means shredding and recycling. For most purposes, a simple longitudinal shredding process is sufficient. The effort to reassemble 4 mm strips of paper into their original form is too expensive for all but the most critical records. That effort is insurmountable if the shredding process mixes the documents with large quantities of other documents. Scanning the strips and puzzling out the original content is however possible. Cross-cut shredders are the best practice today. Even then, the shredded documents should be protected until they can be pulped.

Physical destruction of digital storage media has similar requirements. The ecological factors are much greater with PCs, hard drives, thumb drives, and SIM cards. The following processes are required for R2 certification. It is surprisingly common for people to drill a hole through a hard drive to render it inoperable, which it certainly does. But only the data at the drill site is actually destroyed. The rest ...