SanDisk has launched a new type of SD memory card - the WORM card, a "Write Once Read Many" option for professional uses such as police investigations, court testimony, electronic voting and other applications where data files must be protected from alteration or deletion.

Conventional rewritable memory cards do not meet legal requirements to prevent data tampering, so the digital data written to SanDisk SD WORM cards is effectively locked as soon as it is recorded with no physical way to alter or delete individual recorded files.

Despite this extra protection, viewing the data is as you normally would, and readable in any standard SD slot attached to a computer or other SD-compatible device.

SanDisk say the WORM cards offer 100-year archive life - when kept under appropriate storage conditions - and are currently available in worldwide in 128-megabyte capacity with higher capacities expected later in the year.