Solid state drive erasure proves harder than expected

Deleting data from solid state drives (SSDs) is proving impossible using current software tools, academics have warned.

A paper called Reliably Erasing Data From Flash-Based SSDs (PDF) written by a team at the University of California suggests that traditional software erasing techniques designed for hard drives are not applicable to solid state technology.

"We found that none of the available software techniques for sanitising individual files were effective," the team reported.

While most SSD manufacturers include applications for overwriting data on the drives, the team found that this software is often ill-suited to the task or simply not doing the job. Wiping techniques are usually effective, but lack certain safeguards.

"The internals of an SSD differ in almost every respect from a hard drive, so assuming that the erasure techniques that work for hard drives will also work for SSDs is dangerous," the study found.

The team found that, after creating 1,000 test files, 16 were recoverable using standard techniques.

In one case a manufacturer's recommended wiping instructions left all the data intact on the drive, and some vendors left the encryption key store on the drives intact.