is available that overwrites data, and modern (post-2001) ATA drives include a secure erase command in firmware. However, high-security applications and high-security enterprises can sometimes require that a disk drive be physically destroyed to ensure data is not recoverable, as microscopic changes in head alignment and other effects can mean even such measures are not guaranteed. When the data is encrypted only the encryption key has to be unavailable. Crypto-shredding is the practice of 'deleting' data by (only) deleting or overwriting the encryption keys. See also Crypto-shredding Data erasure References