Newer WD External drives come with password protection and 256-Bit encryption as standard. Even if a password is not set the encryption is still applied to the data written to the drive. The 256-Bit encryption is controlled by ROM on the USB controller. On portable USB powered hard drives the encrypted ROM is on the actual hard drive. On external desktop drives the ROM is on the interface controller within the external case.
Make sure you keep hold of the external case the hard drive was in. Although not always needed, it could be important later on. If you’ve lost data, have a look at our Western Digital Data Recovery service.