Signed Prolific PL2303 Device Drivers
For some time, users of Prolific USB-Serial adapters have been left without signed drivers for OS X. With the release of OS X v10.11 El Capitan the only way to enable unsigned drivers was to disable the OS X System Integrity Protection which left your Mac susceptible to a variety of attack vectors. However, Prolific has finally released signed drivers for their popular PL2303 series USB devices.
The signed Prolific device drivers can be downloaded here. There are 64-bit versions for El Capitan, Yosemite and Mavericks. In addition, older drivers for Mountain Lion, Lion, and Snow Leopard are also available on the page.
Those of you with Prolific devices can now use them with the same security as users of other devices.