Hi all, if you looked a little bit into boarding pass barcodes you might know that at the end of the common data there's an airline specific field. Out of pure curiosity (I don't think there's anything to be gained from this), I'd like to figure out what they're stuffing in there . The data is too short to really contain sensitive information, so personally I feel comfortable posting it here, and hope some of you might join in, but use your own judgement.

NB: if you post, replace spaces with dots (or something else, if you get a dot in there). The forum combines multiple spaces into one. Not doing this will confuse/mangle any effort to understand these bits!

So far, I have seen, at the end of the barcode:

* "*30600000K09..LHG...." - I get this on most of my LH/LX/OS flights. LHG matches my status (Senator).
* "*30601023K09..LHG...." - got this from OS on getting rebooked by Austrian, on a delayed Austrian flight, to another Austrian flight, but originally was LH booking.
* "*30601023K09........." - got this from OS/LH on the same rebooking as the previous one, where they did in fact "forget" my status for whatever reason. Unlike above, this was a LH flight.
* "*30601019K0A02LHGFASTR" - got this from TK on a regular business class booking, nothing special happened that I'm aware of

So far, my theory is - all guess of course:
* '*' - 1 character ID or separator. Might indicate Star Alliance, but might also just be "here starts different data"
* '3' - 1 character possibly version number for the data. The standard parts in the barcode do this too (e.g. version "8" is current on the main passenger detail block).
* '06' - 2 character possibly a sub-block length. Again the other bits in the barcode use 2-character length indicators to make blocks of data, and this lines up with the 09 and 0A later.
* '00'/'01' - 2 character, no clue - that this is a 2-character field is also just a guess based on the numbers.
* '000'/'019'/'023' - 3 character, no clue - again, even the length of the field is a guess.
* 'K' - no clue. But if the 06 is a sub-block length, that sub-block ends after the K.
* '09'/'0A' - 2 character possibly a sub-block length again. 0A is hexadecimal 10, as is done in other places in the barcode. And it lines up to the end of the data! Smells like a pretty good guess.
* ' ' / '02' - 2 characters probably, no clue.
* 'LHG' - quite obviously the *A status airline and level.
* spaces / 'FASTR' - not sure if it's 'FAST' + 'R' in 2 fields or 1 field with 'FASTR' but I believe this might be related to security or immigration fast track bits. NB: the non-airline-specific barcode data already contains a Y/N fast track indicator, it makes little sense to repeat it here and LH only having spaces kinda confirms that.

Anyway if we get a few more of these, maybe we can divinate some meaning!