(Bit Layout)
(Bit Layout)
Line 21: Line 21:
 
| 4:0 4:6 || null || ||
 
| 4:0 4:6 || null || ||
 
|-
 
|-
| 4:7 - 5:7 || varying ||  || date?
+
| 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, issuer id maybe?
 
| 6 - 12 || 0x00 0x49 0x24 0x92 0x49 0x24 0x92 || || fixed in all samples, issuer id maybe?

Revision as of 16:55, 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

Bit Layout

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, issuer id maybe?
13 - 196 todo todo

Content is available under Creative Commons License SA 4.0 unless otherwise noted.