In the US, the 2D barcode (PDF417) contains no signature, only a plaintext duplicate of the information on the face of the card. It's intended purely for conven

In the US, the 2D barcode (PDF417) contains no signature, only a plaintext duplicate of the information on the face of the card. It's intended purely for convenience. Nonetheless, it's not too uncommon for bouncers to use an app to read the barcode because counterfeiters will surprisingly often generate the barcode improperly (causing failure to parse against the AAMVA specification) or outright duplicate it from another ID such that none of the information matches the face of the card. The specification for the barcode payload is a bit obtuse but it's available online and there are plenty of libraries out there for parsing and generating them. Most US driver's licenses also include a 1D barcode along the top edge that contains just an excerpt of the information from the face. This is also according to an AAMVA standard.