MagTek Bluetooth MagneSafe V5 Swipe Reader - Manual (Page 84)

Bluetooth MagneSafe V5 Swipe Reader
76
Ordering the decrypted blocks 1st to last we get:
HEX ASCII
3B35343532333030 ;5452300
3535313232373138 55122718
393D303830343332 9=080432
3130303030303030 10000000
373235303F000000 7250?
We can ignore the last three bytes because they are all hex 00 and fall
after the End Sentinel.
ASCII string ";5452300551227189=080432100000007250?"
This is an accurate decryption of the track.
Track 3 encrypted data
Block # 1 E31234A91059A0FB
2 FE627954EE21868A
3 EE3979540B67FCC4
4 0F61CECA54152D1E
Appendix A tells us to decrypt the last block:
0F61CECA54152D1E TDES Dec with 27F66D5244FF621E AA6F6120EDEB427F
gets DE0949643B57C3C4
XOR EE3979540B67FCC4
gets 3030303030303F00 (decrypted last block)
Continue on in reverse block order:
EE3979540B67FCC4 TDES Dec with 27F66D5244FF621E AA6F6120EDEB427F
gets CB5F4964DE11B6BA
XOR FE627954EE21868A
gets 353D303030303030 (decrypted block 3)
Continue on in reverse block order:
FE627954EE21868A TDES Dec with 27F66D5244FF621E AA6F6120EDEB427F
gets D32A0499226994CF
XOR E31234A91059A0FB
gets 3038303032303434 (decrypted block 2)
Continue on in reverse block order:
E31234A91059A0FB TDES Dec with 27F66D5244FF621E AA6F6120EDEB427F
gets 2B35313633343939 (decrypted block 1)
Ordering the decrypted blocks 1st to last we get:
HEX ASCII
2B35313633343939 +5163499
3038303032303434 08002044
353D303030303030 3=000000
3030303030303F00 000000?
We can ignore the last byte because it is hex 00 and falls after the
End Sentinel.
ASCII string "+5163499080020443=000000000000? "
This is an accurate decryption of the track.