Encrypting a device to securely wipe it is not unheard of. Similar to running dd...

hnick on Feb 13, 2020 | parent | context | favorite | on: Court rules that people can't be locked up indefin...

Encrypting a device to securely wipe it is not unheard of. Similar to running dd over it, but more noise to hopefully remove any lingering magnetic patterns. In such a case there's no need to retain the key.