Back in my day we locked up the hard drives in a safe at night, and destroyed them with a heavy hammer and then off to the burn bag. 
Shipboard, emergency destruction of paper and computer files was done with special hand grenades. Put the grenade in a file cabinet drawer or wastebasket and POOF! The equipment itself was smashed with a hatchet. No messin' around with digital erasing or shredders. (This was done to keep materials from enemy hands if the ship was going to be captured.) Basically, if the enemy is going to board your ship, it's your duty to destroy it first.
The Pueblo failed in that duty. 
