KDE PIM/KItinerary/Trenitalia Barcode: Difference between revisions

Revision as of 17:56, 11 June 2019

always 67 bytes
exactly for one passenger/leg
does not seem to contain signatures, checksums or compression, based on minimal bit pattern changes on adjacent tickets
a lot less null bytes when PNR/seat reservation are present (ie. highspeed train tickets?)
there is a unique, globally sequential ticket number, 2017 in the 600M range, 2019 in the 1B range, which suggests 32bit might be a bit short for this

Byte:Bit (MSB)	Content	Meaning	Notes
0:0 - 4:7	0x20 0x14 0xC2 0x08 0x10	header?	fixed value in all samples
5:0 - 7:7		date?	varies between samples
8:0 - 13:4	null
13:5 - 14:3	100 xxxx		0000 for Italian stations codes (UIC 83.....), 0111 for international destination?
14:4 - 17:3	24 bit uint	UIC station code of departure	only for Italian destinations apparently
17:4 - 18:2	100 xxxx		see above
18:3 - 21:2	24 bit uint	UIC station code of arrival	see above
21:3 - 22:1		unknown	22:1 seems 0 in all samples, the rest varies
22:2 - 24:1	16 bit uint	train number	could be as little as 14 bits too, no train number > 16k has been observed
24:3 - 29:7	null
30:0 - 31:1			null if no PNR present, content unknown
31:2 - 32:0	7 bit uint	seat number	seat row for trains with an airplane-like numbering scheme
32:1 - 32:2	null
32:3 - 32:6	4 bit uint	seat column as hex number	0 for trains without an airplane-like numbering scheme
32:7 - 36:6	all 0 or all 1		always all 0 for no PNR, but can also be 0 when PNR present
36:7 - 38:7			null if no PNR present, content unknown
39:0 -43:3	null
43:4 - 44:3	1010 0110 or null	unknown	fixed value with PNR present, null otherwise
44:4 -45:7	null
46:0 - 50:7		unknown	null if no PNR present, unknown content otherwise
49:0 - 49:7	null
50:0 - 50:7		unknown	null if no PNR present, unknown content otherwise
51:0 - 57:7	0x0B 0x65 0x23 0x18 0x40 0xE6 0xC0		fixed in all samples?
58:0 - 58:3	null		might be part of the ticket number?
58:4 - 62:3	32 bit uint	ticket number
63:4 - 65:7	null
66:0 - 66:7			varies between samples, same as 6:4 - 7:3?

there is one sample where the departure and arrival UIC station codes are equal, contrary to what's in the corresponding PDF
for international destinations the station code does not actually seem to be a valid UIC station code, but there is only one sample to back this up so far
It seems plausible that the coach number is also encoded given the seat number is, 30:0 - 31:1 would seem like the obvious range. In the sample data this does not seem the case with any obvious encoding.
Is the train type derived from the train number, or is that also encoded? 21:3 -22:1 would seem to be the obvious range for that, but so far no correlation to current samples found.
Is the class encoded somewhere?
Date/time encoding is still a mystery.
Is the PNR encoded? 46-50 seems like a plausible range for that. 36^5 possible values, ie. needs >= 26 bit.
What is the "CP Code" in the PDF, and is that encoded somewhere? -> unlikely based on comparing adjacent codes

@@ Line 36: / Line 36: @@
 | 31:2 - 32:0 || 7 bit uint || seat number || seat row for trains with an airplane-like numbering scheme
 |-
-| 32:1 - 32:2 || || unknown ||
+| 32:1 - 32:2 || null ||  ||
 |-
 | 32:3 - 32:6 || 4 bit uint || seat column as hex number || 0 for trains without an airplane-like numbering scheme
 |-
-| 32:7 - 38:7 || || || null if no PNR present, content unknown
+| 32:7 - 36:6  || all 0 or all 1 || || always all 0 for no PNR, but can also be 0 when PNR present
+|-
+| 36:7 - 38:7 || || || null if no PNR present, content unknown
 |-
 | 39:0 -43:3 || null ||  ||