Abstract: A method and apparatus for protecting vehicle data from a vehicle includes identifying the vehicle data to be included in output from a processor that is designated for protection, selecting a digital watermark based on a manner in which the output is subject to at least one of observation or interception, applying the digital watermark to the vehicle data to obtain watermarked output for output from the processor, and communicating a watermark identifier over a communication link of the vehicle to a location external from the vehicle. Detection of the digital watermark in data outside of the vehicle based upon the watermark identifier may be used to determine misuse of the vehicle data.