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They do. I’ve been to bars where they verify the 2D barcode on the back. I don’t know if you need to be a bar to get the verification system.

_moof 5y ago
It’s just a copy of the info printed on the card, in a standard barcode format.
jcrawfordor 5y ago
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.
- Animats 5y ago
  "QR and Barcode Scanner" from F-Droid will decode those 2-dimensional barcodes on a CA driver's license. It's mostly the same info that's on the front. You see it as lines of raw unparsed text with that program.
- nemo1618 5y ago
  Sorry, pet peeve of mine -- "obtuse" means "slow or dim-witted;" you want "abstruse," which means "difficult to comprehend." Granted, using "obtuse" in this way is apparently becoming more common, so this is probably a losing battle... https://www.merriam-webster.com/dictionary/obtuse#note- https://www.merriam-webster.com/dictionary/obtuse#note-
pseudo0 5y ago
Pretty sure it's just a public data format with the same info as on the physical license. The design specs are here: https://www.aamva.org/DL-ID-Card-Design-Standard/ https://www.aamva.org/DL-ID-Card-Design-Standard/ Decent quality fakes will have the correct info in the barcode as well. I guess it weeds out the cheap ones at least? At my cousin's sorority they'd just find a similar-looking girl over 21 who would "lose" her ID and request a replacement, not sure how a bouncer would be able to detect that.

_moof 5y ago

It’s just a copy of the info printed on the card, in a standard barcode format.

jcrawfordor 5y ago

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.

Animats 5y ago
"QR and Barcode Scanner" from F-Droid will decode those 2-dimensional barcodes on a CA driver's license. It's mostly the same info that's on the front. You see it as lines of raw unparsed text with that program.
nemo1618 5y ago
Sorry, pet peeve of mine -- "obtuse" means "slow or dim-witted;" you want "abstruse," which means "difficult to comprehend." Granted, using "obtuse" in this way is apparently becoming more common, so this is probably a losing battle... https://www.merriam-webster.com/dictionary/obtuse#note- https://www.merriam-webster.com/dictionary/obtuse#note-

pseudo0 5y ago

Pretty sure it's just a public data format with the same info as on the physical license. The design specs are here: https://www.aamva.org/DL-ID-Card-Design-Standard/ https://www.aamva.org/DL-ID-Card-Design-Standard/ Decent quality fakes will have the correct info in the barcode as well. I guess it weeds out the cheap ones at least? At my cousin's sorority they'd just find a similar-looking girl over 21 who would "lose" her ID and request a replacement, not sure how a bouncer would be able to detect that.