IPP MS AND DUKPT COMMUNICATIONS PACKETS
MAC-Specific Packets
336 M
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800 SERIES PROGRAMMERS GUIDE
MAC-Specific
Packets
This section describes the master-session MAC generation of received message
packets for the IPP. Two packet formats are specified: Z66 and Z67. The detailed
module design and interface design are discussed. ANSI (Standard) MAC
algorithms are used. The following are the packets in this module:
• Z66: Request MAC
• Z67: Return MAC
• 72: Cancel MAC Session
MAC Packet Z66:
Request MAC
Used by the master device to direct the IPP to generate the MAC of the current
packet. If it is the first Z66 packet, the IPP begins MAC generation. If it is the last
Z66 packet, the IPP completes the MAC calculation for current packet, and
returns the MAC to the master device through the Z67 packet. Otherwise, the IPP
calculates the MAC from current packet and stores it in memory.
Table 86 DUKPT Packet 78 Communication Protocol
Master Device
Transmit
Direction
IPP
78 Packet
• ACK if LRC
• NAK if LRC incorrect
Packet 75 with PIN = 1234
• ACK if LRC
• NAK if LRC incorrect
• EOT after 3 NAKs
Table 87 MAC Packet Z66 Format
Data Element Characteristic Comments
<STX> 1H Start of text, value: 02h
Packet Type 3AN value: Z66
[flag] 1N ANSI (Standard) MAC: ASCII Data: Range: 4–5
• 4 = the last packet
• 5 = the first/middle packet
Binary Data; Range: 6–7
• 6 = the last packet
• 7 = the first/middle packet
[sequence] 2N Range: 00–99
Master Key
Pointer
1N Optional; Range: 0–9
<FS> 1H Field separator, value: 1Ch
Working Key 16H Encrypted working key for DES
<FS> 1H Field separator, value: 1Ch
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