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Copyright (C) 2019 Robin Krahl <robin.krahl@ireas.org>
SPDX-License-Identifier: CC0-1.0
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- Clear passwords from memory.
- Lock password safe in `PasswordSafe::drop()` (see [nitrokey-storage-firmware
  issue 65][]).

[nitrokey-storage-firmware issue 65]: https://github.com/Nitrokey/nitrokey-storage-firmware/issues/65