Comment 1 for bug 1505113

Validating the encryption provider is tricky because Cinder cannot verify that a module does or does not exist in Nova (e.g., nova.volume.encryptors.luks.LuksEncryptor).

Perhaps it would be better to move the encryptors to oslo so they can be shared more easily. In addition, assuming that Nova and Cinder both require some minimum version of the resulting oslo library (e.g., oslo.encryptors), then Cinder could validate the input immediately as suggested in this bug report.