installing and using keyring plugin (no replies)

I was trying to install keyring plugin on MySQL 5.7.18.

I edited my.ini file. It was blank so I added the following text and restarted MySQL.

[mysqld]
early-plugin-load=keyring_file.dll

I ran the following command to install the plugin.

mysql> install plugin keyring_file soname 'keyring_file.dll';

I then ran the following sql to check:

mysql> SELECT PLUGIN_NAME, PLUGIN_STATUS
-> FROM INFORMATION_SCHEMA.PLUGINS
-> WHERE PLUGIN_NAME LIKE 'keyring%';
+--------------+---------------+
| PLUGIN_NAME | PLUGIN_STATUS |
+--------------+---------------+
| keyring_file | ACTIVE |
+--------------+---------------+
1 row in set (0.00 sec)

But when I tried to alter a table to use encryption, I got errors.

mysql> ALTER TABLE t1 ENCRYPTION='Y';
ERROR 3185 (HY000): Can't find master key from keyring, please check keyring
plugin is loaded.

Did I miss a step somewhere?