When reading Encrypting Data for InnoDB / XtraDB you may be lead to believe that if you are using innodb_encrypt_tables=FORCE then you would be unable to access any InnoDB tables that are storing data in plaintext.
|OFF||Disables table encryption|
|ON||Enables table encryption, but allows unencrypted tables|
|FORCE||Enables table encryption, but doesn't allow unencrypted tables|
The variable documentation states it differently:
This could lead to someone having the wrong impression about using FORCE