VeriFone MX800 Series - DUKPT Packet 91: Load Initial Key Response

IPP MS AND DUKPT COMMUNICATIONS PACKETS
Packet 25: Check the DUKPT Engine
M
X
800 SERIES PROGRAMMERS GUIDE 329
DUKPT Packet 91:
Load Initial Key
Response
Response packet to packet 90. Response to controller with confirmation status. If
21 Future Keys are successfully initialized, Packet 91 responds with confirmation.
Else, negative response packet 91 returns.
DUKPT Packet 91
Length
• MAX: 6 characters
• MIN: 6 characters
Table 74 DUKPT Packet 90 Communication Protocol
Master Device
Transmit
Direction
IPP
90 Packet
• ACK if LRC
• NAK if LRC incorrect
• EOT after 3 NAKs
• Initialization of 21 Future Keys
Packet 91 with confirmed status
• ACK if LRC
• NAK if LRC incorrect
• EOT after 3 NAKs
Table 75 DUKPT Packet 91 Format
Data Element Characteristic Comments
<STX> 1H Start of text, Value: 02h
Packet Type 2AN Value: 91
[CS] 1N Confirmation status:
• 0 = Confirmed
• 1 = Not confirmed
• 2 = (IPP7 only) Error; incorrect key length.
Confirmation status 2 only applies to IPP7. It
indicates that the length of the initial PIN
encryption key does not comply with 1DES or
3DES DUKPT mode, as follows:
<ETX> 1H End of text, value: 03h
{LRC} 1H Error check character
Initial PIN
encryption key length
(through packet 90)
sent by the master device
IPP7 Current
DUKPT Mode
[CS] response from
the IPP
16AH 3DES 2
32AH 1DES 2