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Command: |
Generate a transaction response with Auth Para generated by the Acquirer. |
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Notes: |
The command enables the Acquirer to generate the response message to a terminal, when the Acquirer is delegated to authorise a transaction on behalf of a Card Issuer. The Authorisation Parameter, Auth Para, is generated directly and included in the output MAC if appropriate. Auth Para is included if the transaction is approved, and not included if the transaction is declined. |
This function can also be used to generate a MAC and update the Terminal Key for an Administration message response. For this purpose, the AP Include flag is E.
If the Host is unable to support binary data transfers, the command can be used in standard (ASCII character) asynchronous mode (in which the message to be MACed is transferred in expanded hexadecimal notation).
The AT, STAN and CATID pointers are in integral bytes and refer to the locations of the various values in the binary message. They are therefore the same irrespective of the communications mode in use. In standard async mode, they can be used only AFTER re-compression to a binary message.
AT is 6 bytes long (12 digits).
STAN is 3 bytes long (6 digits).
CATID is 8 bytes long (16 digits).
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 RK. |
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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 |
Encrypted under LMK 10. |
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AP include flag |
1 A |
I = include, E = exclude. |
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CD |
16 H |
Present only if flag is I. |
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AT pointer |
3 H |
Pointer to message text. Present only if flag is I. |
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STAN pointer |
3 H |
Pointer to message text. Present only if flag is I. |
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CATID pointer |
3 H |
Pointer to message text. Present only if flag is I. |
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Field |
Length & Type |
Details | |
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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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RESPONSE MESSAGE |
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Message header |
n A |
Returned to the Host unchanged. |
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Response code |
2 A |
Value RL. |
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Error code |
2 N |
00 : No errors 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 |
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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