Physical destruction

Physical destruction is the Destroy method of NIST SP 800-88 Rev. 2. The techniques the guideline associates with it are disintegration, pulverisation, melting, incineration and shredding, and the intended result is media that cannot be read even with state-of-the-art laboratory methods and cannot store data again. Partial damage, such as drilling or bending a drive, does not meet that bar. Because rising data density can leave readable fragments, the guideline also advises against shredding and pulverising electronic storage media for anything but the lowest categories of data. Destruction suits media where other methods fail or cannot be verified: write-once optical discs, damaged drives that no longer respond to commands, and flash storage whose controller offers no trustworthy purge.

Destruction is the strongest option, but it is not automatically the right one. It ends any chance of reuse or resale, it usually costs more per device than clearing or purging, and it has an environmental cost. When destruction is outsourced, chain of custody records and a certificate of destruction give the organisation evidence that each device was destroyed. Degaussing is often mistaken for destruction, but NIST places it under Purge, and does not count it as destruction even when it leaves a drive inoperable; it has no effect on non-magnetic media.

Exam relevance: a scenario may involve highly sensitive media, an unreliable alternative, or media leaving organisational control, and ask for the appropriate method. Candidates are expected to choose destruction where purging cannot be relied on or where the sensitivity calls for it, and to recognise the records that should accompany it.