Steps to reproduce:
# create a volume type (admin tenant)
# create encryption type - >  (admin tenant) 
encryption_prov = nova.volume.encryptors.luks.LuksEncryptor
key_size = 256
cipher = aes-xts-plain64
control_location = front-end

# add non-admin tenant to the role creator

# create a volume (non-admin) tenant.

Here are some shows:
Tenants:
89517260b9504830a0d3154cf061f36d | tempest-TestEncryptedCinderVolumes-57557031

cinder backend:
[root@localhost devstack]# cinder get-pools --detail
+-----------------------------+------------------------------------------------------------------------------+
| Property                    | Value                                                                        |
+-----------------------------+------------------------------------------------------------------------------+
| QoS_support                 | False                                                                        |
| allocated_capacity_gb       | 1                                                                            |
| backend_state               | up                                                                           |
| driver_version              | 3.0.0                                                                        |
| filter_function             | None                                                                         |
| free_capacity_gb            | 22.8                                                                         |
| goodness_function           | None                                                                         |
| location_info               | LVMVolumeDriver:localhost.localdomain.localdomain:stack-volumes-lvm_2:thin:0 |
| max_over_subscription_ratio | 20.0                                                                         |
| multiattach                 | True                                                                         |
| name                        | localhost.localdomain.localdomain@lvm_2#lvm_2                                |
| pool_name                   | lvm_2                                                                        |
| provisioned_capacity_gb     | 1.0                                                                          |
| reserved_percentage         | 0                                                                            |
| storage_protocol            | iSCSI                                                                        |
| thick_provisioning_support  | False                                                                        |
| thin_provisioning_support   | True                                                                         |
| timestamp                   | 2018-06-07T05:12:27.189877                                                   |
| total_capacity_gb           | 22.8                                                                         |
| total_volumes               | 2                                                                            |
| vendor_name                 | Open Source                                                                  |
| volume_backend_name         | lvm_2                                                                        |
+-----------------------------+------------------------------------------------------------------------------+



# type:
[root@localhost devstack]# cinder type-show e07ae5bf-773c-4f44-b39b-7d230dc7dbfd
+---------------------------------+----------------------------------------------------------+
| Property                        | Value                                                    |
+---------------------------------+----------------------------------------------------------+
| description                     | None                                                     |
| extra_specs                     |                                                          |
| id                              | e07ae5bf-773c-4f44-b39b-7d230dc7dbfd                     |
| is_public                       | True                                                     |
| name                            | tempest-volume-typeTestEncryptedCinderVolumes-1547077427 |
| os-volume-type-access:is_public | True                                                     |
| qos_specs_id                    | None                                                     |
+---------------------------------+-----------------------


[root@localhost devstack]# cinder encryption-type-show e07ae5bf-773c-4f44-b39b-7d230dc7dbfd
+--------------------------------------+-------------------------------------------+-----------------+----------+------------------+
| Volume Type ID                       | Provider                                  | Cipher          | Key Size | Control Location |
+--------------------------------------+-------------------------------------------+-----------------+----------+------------------+
| e07ae5bf-773c-4f44-b39b-7d230dc7dbfd | nova.volume.encryptors.luks.LuksEncryptor | aes-xts-plain64 | 256      | front-end        |
+--------------------------------------+-------------------------------------------+-----------------+----------+------------------+




[root@localhost devstack]# cinder show 0951c21a-b43e-4ab5-926d-bd44e9ddfa06
+--------------------------------+----------------------------------------------------------+
| Property                       | Value                                                    |
+--------------------------------+----------------------------------------------------------+
| attached_servers               | []                                                       |
| attachment_ids                 | []                                                       |
| availability_zone              | nova                                                     |
| bootable                       | false                                                    |
| consistencygroup_id            | None                                                     |
| created_at                     | 2018-06-07T05:00:33.000000                               |
| description                    | None                                                     |
| encrypted                      | True                                                     |
| id                             | 0951c21a-b43e-4ab5-926d-bd44e9ddfa06                     |
| metadata                       |                                                          |
| migration_status               | None                                                     |
| multiattach                    | False                                                    |
| name                           | tempest-TestEncryptedCinderVolumes-volume-84245745       |
| os-vol-host-attr:host          | localhost.localdomain.localdomain@lvm_2#lvm_2            |
| os-vol-mig-status-attr:migstat | None                                                     |
| os-vol-mig-status-attr:name_id | None                                                     |
| os-vol-tenant-attr:tenant_id   | 89517260b9504830a0d3154cf061f36d                         |
| replication_status             | None                                                     |
| size                           | 1                                                        |
| snapshot_id                    | None                                                     |
| source_volid                   | None                                                     |
| status                         | error_deleting                                           |
| updated_at                     | 2018-06-07T05:01:49.000000                               |
| user_id                        | acdeff6883c94003be639c2afd4c49e9                         |
| volume_type                    | tempest-volume-typeTestEncryptedCinderVolumes-1547077427 |
+--------------------------------+----------------------------------------------------------+