Simson Garfinkel

Simson Garfinkel researches computer security, privacy and digital forensics. With Abhi Shelat, he studied whether used hard disk drives retained readable information after disposal or resale. Their 2003 paper transformed a general concern about confidentiality into an investigation of actual storage devices.^[ref]

The researchers acquired 158 drives between November 2000 and August 2002, recorded their provenance and examined copied device contents. Some drives were damaged or unreadable; others retained recoverable data. The paper distinguishes ordinary access through a file system from information remaining outside its live names and records. It also cautions that the sample does not establish a population-wide prevalence.^[ref]

An original storage example makes the distinction concrete. Suppose a toy file system holds a document in four 512-byte file data blocks. Removing its name from a file-system directory and marking those blocks reusable can leave all $4\times 512=2048$ content bytes unchanged. The file deletion changed live bookkeeping, while this stipulated model performed zero overwrites of the document's contents. Other file systems can behave differently, but disappearing from a directory listing alone does not prove data sanitization.

The experiment motivates testing a storage claim at the level it concerns: absence of a live filename and absence of recoverable former content are different observations.