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Command: |
Generate a response message to be sent to the Terminal, with Auth Para generated by the Card Issuer. |
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Notes: |
The command is used where a Card Issuer has generated Auth Para and sent it to the Acquirer encrypted under a Zone PIN Key (ZPK). Its main functions are to generate the MAC for the response message and to update the Terminal Key. If the Host is unable to support binary data transfers, the command can be used in standard (ASCII character) asynchronous mode (in which mode the message to be MACed is transferred in expanded hexadecimal notation). |
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Field |
Length & Type |
Details | |
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COMMAND MESSAGE |
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Message header |
m A |
(Subsequently returned to the Host unchanged). |
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Command code |
2 A |
Value RM. |
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Terminal key |
16 H |
The terminal key encrypted under LMK pair 14-15. |
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AB |
16 H |
Formed in accordance with the terminal specification by the Host. |
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MAC residue (MR1 ) |
8 H |
MR from the request message encrypted under LMK 10. |
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AP include flag |
1 A |
I = include, E = exclude. |
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Zone PIN key |
16H or |
ZPK encrypted under LMK pair 06-07. Present only if AP include flag is I. |
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Auth Para |
16 H |
AP encrypted under a variant of ZPK. Present only if AP include flag is I. |
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EITHER |
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For Binary Communications Modes: |
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Message length |
3 H |
X’001 to X’320 indicating the length of the next field. |
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Message text |
n B |
1 to 800 bytes of message. |
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OR |
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For Standard Async Communications Mode: |
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Message length |
3 H |
X’002 to X’320 indicating the number of characters in the next field. |
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Message text |
n H |
2 to 800 hexadecimal characters representing 1 to 400 bytes of message. |
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End message delimiter |
1 C |
Optional. Must be present if a message trailer is present. Value X’19. |
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Message trailer |
n A |
Optional. Maximum length 32 characters. |
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Field |
Length & Type |
Details | |
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RESPONSE MESSAGE |
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Message header |
n A |
Returned to the Host unchanged. |
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Response code |
2 A |
Value RN. |
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Error code |
2 N |
00 : No errors 11 : Zone PIN key parity error 12 : No keys loaded in user storage 13 : LMK error; report to supervisor 15 : Error in input data 21 : Invalid user storage index 80 : Message length error (including odd number of characters when using standard async mode) 90 : Communications link parity error 91 : Communications link LRC error 92 : Transparent async data length error |
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MAC residue (MR2) |
8 H |
The MR from the response message encrypted under LMK 10. |
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MAC |
8 H |
Newly-generated MAC. |
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Terminal key |
16 H |
The new derived TK encrypted under LMK pair 14-15. |
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End message delimiter |
1 C |
Present only if present in the command message. Value X’19. |
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Message trailer |
n A |
Present only if present in the command message. Maximum length 32 characters. |
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