Anonymouth – Document Anonymization Tool

Here's a stupid but effective way I came up with to delete the data in files when they are too large to be stored in RAM:

Use dd on the device where the file is stored.

Files intended for eventual deletion can be stored on their own dedicated virtual block devices, or "file-backed virtual disks".

Unless things have changed, on OpenBSD these virtual block devices can be created from /dev/vnd.

To create a location to store the file(s) at, create an empty "backing" file with dd, associate it with a vnd, newfs the vnd and mount it.

To delete all the files on the mounted vnd, either umount and dd if=/dev/zero of=/dev/vnd{no}d or dd if=/dev/zero of=rvnd{no}d and umount.

One can also configure a cryptographic disk device over the vnd using a random throwaway password.