Which process involves removing information from media so that recovery is impossible?

The process that involves removing information from media so that recovery is impossible is best defined as "wiping." Wiping refers specifically to the methods used to eliminate all data from a storage device in such a way that retrieving any part of that data is not feasible, effectively ensuring that sensitive information cannot be recovered using standard means.

While sanitizing or purging might imply that data has been rendered unrecoverable, it often refers to broader methods of data removal that may include wiping as well as other techniques. In the context of ensuring that data is permanently gone and cannot be recovered at all, "wiping" is the most precise term. This is particularly critical in environments where data security is paramount, as merely deleting files or reformatting a drive does not adequately address the need for complete data destruction.

Encryption, on the other hand, protects data by making it unreadable without the correct decryption key, while backing up involves creating copies of data for redundancy, neither of which addresses the issue of permanently removing data from a device.