Appendix B - Examples
eDynamo| Secure Card Reader Authenticator | Programmer’s Manual (COMMANDS)
Page 198 of 245 (
D998200115-17
)
The track 2 encrypted data is:
72 4C 5D B7 D6 F9 01 C7
F0 FE AE 79 08 80 10 93
B3 DB FE 51 CC F6 D4 83
E7 89 D7 D2 C0 07 D5 39
49 9B AA DC C8 D1 6C A2
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
Because the
Track 2 Encrypted Data Length (HID | GATT | SLIP)
value in the incoming data says
Track 2 encrypted data is 40 bytes long, the host software can truncate the trailing blocks:
Block #
Data
1
724C5DB7D6F901C7
2
F0FEAE7908801093
3
B3DBFE51CCF6D483
4
E789D7D2C007D539
5
499BAADCC8D16CA2
Section
5 Encryption, Decryption, and Key Management
tells us to decrypt the last block first:
499BAADCC8D16CA2
TDES Decrypt with
27F66D5244FF621E AA6F6120EDEB427F
gets
D0BBE2E2FF07D539
, XOR
E789D7D2C007D539
gets
373235303F000000
, which is the
decrypted final block.
Continuing in reverse block order,
E789D7D2C007D539
TDES Decrypt with
27F66D5244FF621E
AA6F6120EDEB427F
gets
82EBCE61FCC6E4B3
, XOR
B3DBFE51CCF6D483
gets
3130303030303030
, which is decrypted block 4.
Continuing in reverse block order,
B3DBFE51CCF6D483
TDES Decrypt with
27F66D5244FF621E
AA6F6120EDEB427F
gets
C9C39E4138B423A1
, XOR
F0FEAE7908801093
gets
393D303830343332
, which is decrypted block 3.
Continuing in reverse block order,
F0FEAE7908801093
TDES Decrypt with
27F66D5244FF621E
AA6F6120EDEB427F
gets
47796C85E4CE30FF
, XOR
724C5DB7D6F901C7
gets
3535313232373138
, which is decrypted block 2.
Continuing in reverse block order,
724C5DB7D6F901C7
TDES Decrypt with
27F66D5244FF621E
AA6F6120EDEB427F
gets
3B35343532333030
, which is decrypted block 1.
Ordering the decrypted blocks first to last gives: