Revision as of 17:34, 4 January 2020

General Observations

always exactly 107 byte
all binary, there are no recognizable ASCII strings in this
the last ~64 byte have very high entropy, suggesting a signature or a compressed section
there's a base64 encoded sequential number printed below the Aztec code on the ticket, containing 24bit.
one barcode seems to be exactly for one journey section

Byte[:Bit] (MSB)	Content	Meaning	Notes
0 - 1	0b0001 0000 0b0000 0010	unknown	fixed in all samples
2	0b1010 0000 or 0b1000 0000	unknown
3	0b0000 0001	unknown	fixed in all samples
4:0 4:6	null
4:7 - 5:7	9 bit day number		day of travel, counted from Jan 1
6 - 12	0x00 0x49 0x24 0x92 0x49 0x24 0x92		fixed in all samples, patterns repeats below
13 - 31	todo	todo
32 - 40	0x89 0x24 0x92 0x49 0x24 0x90 0x60 0x00 0x01		fixed in all samples, repeats a pattern from 6-12
41:0 - 42:0	todo	todo	varies slightly between samples
42:1 - 106:0	64 byte varying		high entropy in all samples, signature?
106:1 - 106:7	null

@@ Line 23: / Line 23: @@
 | 4:7 - 5:7 || 9 bit day number ||  || day of travel, counted from Jan 1
 |-
-| 6 - 12 || 0x00 0x49 0x24 0x92 0x49 0x24 0x92 || || fixed in all samples
+| 6 - 12 || 0x00 0x49 0x24 0x92 0x49 0x24 0x92 || || fixed in all samples, patterns repeats below
 |-
-| 13 - 42:0 || todo || todo ||
+| 13 - 31 || todo || todo ||
+|-
+| 32 - 40 || 0x89 0x24 0x92 0x49 0x24 0x90 0x60 0x00 0x01 || || fixed in all samples, repeats a pattern from 6-12
+|-
+| 41:0 - 42:0 || todo || todo || varies slightly between samples
 |-
 | 42:1 - 106:0 || 64 byte varying || || high entropy in all samples, signature?