User's Manual

PIN Pad 791 Programmer’s Manual (PCI POS-A) UDN PM0103-U Rev. 06
Section 10 – Online transaction messages with DUKPT 2015-04-20
Page255
Uniform Industrial Corp. Proprietary and Confidential Total 342 pages
(Encrypted format)
Field Length Value and description
<STX> 1 <02>
90 2 Message ID
[TR-31 Key
Block]
88 or
104
TR-31 key block with optional header
block that contains KSN.
See Appendix A for detail.
<ETX> 1 <03>
[LRC] 1 Checksum
Message flow:
HOST Direction PIN pad
Message 90


<ACK> (Good LRC)
<NAK> (Bad LRC)
<EOT> (after 3 NAKs)

Message 91
<ACK>/<NAK>/<EOT>

Example:
Clear Text
IPEK key to be loaded: ABCDEF0123456789FEDCBA9876543210
KSN: FFFF9876543210E00000
The resulting 90 message :
<STX>90ABCDEF0123456789FEDCBA9876543210FFFF9876543210E00000<ETX>[LRC]
TR-31 Key Block
Key Block Protecting Key: AA55AA55AA55AA55 3434343434343434
IPEK key to be loaded: ABCDEF0123456789 FEDCBA9876543210
KSN: FFFF9876543210E00000
Key Block Header: B0104B1TX00N0100 KS18FFFF9876543210E00000
Padded IPEK: 0080 ABCDEF0123456789 FEDCBA9876543210 30111D18CC4C
Derived KBEK: 3C50E1B7962F2171DC8643F1D923ABF7
Derived KBMK: 46FBEEB64EAE26A650952DA4F6DD8325
CMAC of (KBH + Padded key data), using KBMK: 93C3D5EBC6C407E4
Use CMAC as IV to do TDES CBC encryption on padded key data, using KBEK:
Encrypted key data: EC86E6E3B24544F97C629FB0E0586A0285D35BA78E9B13FB
Result: <02>90B0104B1TX00N0100KS18FFFF9876543210E00000EC86E6E3B24544F9
7C629FB0E0586A0285D35BA78E9B13FB93C3D5EBC6C407E4<03>