ISO 8583
ISO 8583 is an international standard for financial transaction card originated interchange messaging. It is the International Organization for Standardization standard for systems that exchange electronic transactions initiated by cardholders using payment cards.
ISO 8583 defines a message format and a communication flow so that different systems can exchange these transaction requests and responses. The vast majority of transactions made when a customer uses a card to make a payment in a store (EFTPOS) use ISO 8583 at some point in the communication chain, as do transactions made at ATMs. In particular, both the MasterCard and Visa networks base their authorization communications on the ISO 8583 standard, as do many other institutions and networks.
Although ISO 8583 defines a common standard, it is not typically used directly by systems or networks. It defines many standard fields (data elements) which remain the same in all systems or networks, and leaves a few additional fields for passing network-specific details. These fields are used by each network to adapt the standard for its own use with custom fields and custom usages.
Introduction
The ISO 8583 specification has three parts:
Message format
A card-based transaction typically travels from a transaction-acquiring device, such as a point-of-sale terminal or an automated teller machine (ATM), through a series of networks, to a card issuing system for authorization against the card holder's account. The transaction data contains information derived from the card (e.g., the account number), the terminal (e.g., the merchant number), the transaction (e.g., the amount), together with other data which may be generated dynamically or added by intervening systems. Based on this information, the card issuing system will either authorize or decline the transaction and generate a response message which must be delivered back to the terminal within a predefined time period.
An ISO 8583 message is made of the following parts:
- Message type indicator (MTI)
- One or more bitmaps, indicating which data elements are present
- Data elements, the actual information fields of the message
The placements of fields in different versions of the standard varies; for example, the currency elements of the 1987 and 1993 versions of the standard are no longer used in the 2003 version, which holds currency as a sub-element of any financial amount element. As of June 2017, however ISO 8583:2003 has yet to achieve wide acceptance. ISO 8583 messaging has no routing information, so is sometimes used with a TPDU header.
Cardholder-originated transactions include purchase, withdrawal, deposit, refund, reversal, balance inquiry, payments and inter-account transfers. ISO 8583 also defines system-to-system messages for secure key exchanges, reconciliation of totals, and other administrative purposes.
Message type indicator (MTI)
The message type indicator is a four-digit numeric field which indicates the overall function of the message. A message type indicator includes the ISO 8583 version, the Message Class, the Message Function and the Message Origin, as described below.
ISO 8583 version
The first digit of the MTI indicates the ISO 8583 version in which the message is encoded.
| Code | Meaning |
|---|---|
| 0xxx | ISO 8583:1987 |
| 1xxx | ISO 8583:1993 |
| 2xxx | ISO 8583:2003 |
| 3xxx | Reserved by ISO |
| 4xxx | |
| 5xxx | |
| 6xxx | |
| 7xxx | |
| 8xxx | National use |
| 9xxx | Private use |
Message class
Position two of the MTI specifies the overall purpose of the message.
| Code | Meaning | Usage |
|---|---|---|
| x0xx | Reserved by ISO | |
| x1xx | Authorization message | Determine if funds are available, get an approval but do not post to account for reconciliation. Dual message system (DMS), awaits file exchange for posting to the account. |
| x2xx | Financial messages | Determine if funds are available, get an approval and post directly to the account. Single message system (SMS), no file exchange after this. |
| x3xx | File actions message | Used for hot-card, TMS and other exchanges |
| x4xx | Reversal and chargeback messages | Reversal (x4x0 or x4x1): Reverses the action of a previous authorization. Chargeback (x4x2 or x4x3): Charges back a previously cleared financial message. |
| x5xx | Reconciliation message | Transmits settlement information message. |
| x6xx | Administrative message | Transmits administrative advice. Often used for failure messages (e.g. message reject or failure to apply). |
| x7xx | Fee collection messages | |
| x8xx | Network management message | Used for secure key exchange, logon, echo test and other network functions. |
| x9xx | Reserved by ISO |
Message function
Position three of the MTI specifies the message function which defines how the message should flow within the system. Requests are end-to-end messages (e.g., from acquirer to issuer and back with time-outs and automatic reversals in place), while advices are point-to-point messages (e.g., from terminal to acquirer, from acquirer to network, from network to issuer, with transmission guaranteed over each link, but not necessarily immediately).
| Code | Meaning | Notes |
|---|---|---|
| xx0x | Request | |
| xx1x | Request response | |
| xx2x | Advice | |
| xx3x | Advice response | |
| xx4x | Notification | |
| xx5x | Notification acknowledgement | |
| xx6x | Instruction | ISO 8583:2003 only |
| xx7x | Instruction acknowledgement | |
| xx8x | Reserved for ISO use | Some implementations (such as MasterCard) use for positive acknowledgment.[4] |
| xx9x | Some implementations (such as MasterCard) use for negative acknowledgement.[5] |
Message origin
Position four of the MTI defines the location of the message source within the payment chain.
| Code | Meaning |
|---|---|
| xxx0 | Acquirer |
| xxx1 | Acquirer repeat |
| xxx2 | Issuer |
| xxx3 | Issuer repeat |
| xxx4 | Other |
| xxx5 | Other repeat |
| xxx6 | Reserved by ISO |
| xxx7 | |
| xxx8 | |
| xxx9 |
Examples
Given an MTI value of 0110, the following example lists what each position indicates:
- 0xxx → version of ISO 8583 (0 = 1987 version)
- x1xx → class of the message (1 = authorization message)
- xx1x → function of the message (1 = response)
- xxx0 → who began the communication (0 = acquirer)
Therefore, MTI 0110 is an authorization response message sent by the acquirer.
Bearing each of the above four positions in mind, an MTI will completely specify what a message should do, and how it is to be transmitted around the network. Unfortunately, not all ISO 8583 implementations interpret the meaning of an MTI in the same way. However, a few MTIs are relatively standard:
| MTI | Meaning | Usage |
|---|---|---|
| 0100 | Authorization Request | Request from a point-of-sale terminal for authorization for a cardholder purchase |
| 0110 | Authorization Response | Request response to a point-of-sale terminal for authorization for a cardholder purchase |
| 0120 | Authorization Advice | When the point-of-sale device breaks down and you have to sign a voucher |
| 0121 | Authorization Advice Repeat | If the advice times out |
| 0130 | Issuer Response to Authorization Advice | Confirmation of receipt of authorization advice |
| 0200 | Acquirer Financial Request | Request for funds, typically from an ATM or pinned point-of-sale device |
| 0210 | Issuer Response to Financial Request | Issuer response to request for funds |
| 0220 | Acquirer Financial Advice | e.g. Checkout at a hotel. Used to complete transaction initiated with authorization request |
| 0221 | Acquirer Financial Advice Repeat | If the advice times out |
| 0230 | Issuer Response to Financial Advice | Confirmation of receipt of financial advice |
| 0320 | Batch Upload | File update/transfer advice |
| 0330 | Batch Upload Response | File update/transfer advice response |
| 0400 | Acquirer Reversal Request | Reverses a transaction |
| 0510 | Batch Settlement response | Card acceptor reconciliation request response |
| 0800 | Network Management Request | Hypercom terminals initialize request. Echo test, logon, logoff etc. |
| 0810 | Network Management Response | Hypercom terminals initialize response. Echo test, logon, logoff etc. |
| 0820 | Network Management Advice | Key change |
Bitmaps
In ISO 8583, a bitmap is a field or subfield within a message, which indicates whether other data elements or data element subfields are present elsewhere in the message.
A field is considered to be present only when the corresponding bit in the bitmap is set. For example, a hex with value 0x82 (decimal 130) is binary 1000 0010, which means fields 1 and 7 are present in the message and fields 2, 3, 4, 5, 6 and 8 are not.
The bitmap may be represented as 8 bytes of binary data or as 16 hexadecimal characters (0-9, A-F) in the ASCII or EBCDIC character sets. A message will contain at least one bitmap, called the primary bitmap, which indicates which of data elements 1 to 64 are present. The presence of an optional secondary bitmap is also indicated by the first bit in the primary bitmap. If present, the secondary bitmap indicates whether data elements 65 to 128 are present. Similarly, a tertiary bitmap can be used to indicate the presence of fields 129 to 192, although these data elements are rarely used.
Examples
Given a bitmap value of 22 10 00 11 02 C0 48 04,
- 0x22 = 0010 0010 (counting from the left, the third and seventh bits are 1, indicating that fields 3 and 7 are present)
- 0x10 = 0001 0000 (the first bit corresponds to field 9, so the fourth bit here indicates field 12 is present)
- 0x00 = 0000 0000 (no fields present)
- 0x11 = 0001 0001 (fields 28 and 32 are present)
- 0x02 = 0000 0010 (field 39 is present)
- 0xC0 = 1100 0000 (fields 41 and 42 are present)
- 0x48 = 0100 1000 (fields 50 and 53 are present)
- 0x04 = 0000 0100 (field 62 is present)
| nth bit | 0 | 10 | 20 | 30 | 40 | 50 | 60 |
|---|---|---|---|---|---|---|---|
| 1234567890 | 1234567890 | 1234567890 | 1234567890 | 1234567890 | 1234567890 | 1234 | |
| Bitmap | 0010001000 | 0100000000 | 0000000100 | 0100000010 | 1100000001 | 0010000000 | 0100 |
Therefore, the given bitmap defines the following fields present in the message:
3, 7, 12, 28, 32, 39, 41, 42, 50, 53, 62
Data elements
Data elements are the individual fields carrying the transaction information. There are up to 128 data elements specified in the original ISO 8583:1987 standard, and up to 192 data elements in later releases. The 1993 revision added new definitions, deleted some, while leaving the message format itself unchanged.
While each data element has a specified meaning and format, the standard also includes some general purpose data elements and system- or country-specific data elements which vary enormously in use and form from implementation to implementation.
Each data element is described in a standard format which defines the permitted content of the field (numeric, binary, etc.) and the field length (variable or fixed), according to the following table:
| Abbreviation | Meaning |
|---|---|
| a | Alpha, including blanks |
| n | Numeric values only |
| s | Special characters only |
| an | Alphanumeric |
| as | Alpha & special characters only |
| ns | Numeric and special characters only |
| ans | Alphabetic, numeric and special characters. |
| b | Binary data |
| z | Tracks 2 and 3 code set as defined in ISO/IEC 7813 and ISO/IEC 4909 respectively |
| . or .. or ... | variable field length indicator, each . indicating a digit. |
| x or xx or xxx | fixed length of field, or maximum length in the case of variable length fields. |
Additionally, each field may be either fixed or variable length. If variable, the length of the field will be preceded by a length indicator.
| Type | Meaning |
|---|---|
| Fixed | no field length used |
| LLVAR or (..xx) | Where 0 < LL < 100, means two leading digits LL specify the field length of field VAR |
| LLLVAR or (...xxx) | Where 0 < LLL < 1000, means three leading digits LLL specify the field length of field VAR |
| LL and LLL are hex or ASCII. A VAR field can be compressed or ASCII depending of the data element type. | LL can be one or two bytes. For example, if compressed as one hex byte, '27x means there are 27 VAR bytes to follow. If ASCII, the two bytes '32x, '37x mean there are 27 bytes to follow. Three-digit field length LLL uses two bytes with a leading '0' nibble if compressed, or three bytes if ASCII. The format of a VAR data element depends on the data element type. If numeric it will be compressed, e.g. 87456 will be represented by three hex bytes '087456x. If ASCII then one byte for each digit or character is used, e.g. '38x, '37x, '34x, '35x, '36x. |
Examples
| Field Definition | Meaning |
|---|---|
| n 6 | Fixed length field of six digits |
| n.6 | LVAR numeric field of up to 6 digits in |
| a..11 | LLVAR alpha field of up to 11 characters in length |
| b...999 | LLLVAR binary field of up to 999 bits in length |
ISO-defined data elements
| Data field | Type | Usage |
|---|---|---|
| 1 | b 64 | Second Bitmap |
| 2 | n ..19 | Primary account number (PAN) |
| 3 | n 6 | Processing code |
| 4 | n 12 | Amount, transaction |
| 5 | n 12 | Amount, settlement |
| 6 | n 12 | Amount, cardholder billing |
| 7 | n 10 | Transmission date & time |
| 8 | n 8 | Amount, cardholder billing fee |
| 9 | n 8 | Conversion rate, settlement |
| 10 | n 8 | Conversion rate, cardholder billing |
| 11 | n 6 | System trace audit number (STAN) |
| 12 | n 6 | Local transaction time (hhmmss) |
| 13 | n 4 | Local transaction date (MMDD) |
| 14 | n 4 | Expiration date |
| 15 | n 4 | Settlement date |
| 16 | n 4 | Currency conversion date |
| 17 | n 4 | Capture date |
| 18 | n 4 | Merchant type, or merchant category code |
| 19 | n 3 | Acquiring institution (country code) |
| 20 | n 3 | PAN extended (country code) |
| 21 | n 3 | Forwarding institution (country code) |
| 22 | n 3 | Point of service entry mode |
| 23 | n 3 | Application PAN sequence number |
| 24 | n 3 | Function code (ISO 8583:1993), or network international identifier (NII) |
| 25 | n 2 | Point of service condition code |
| 26 | n 2 | Point of service capture code |
| 27 | n 1 | Authorizing identification response length |
| 28 | x+n 8 | Amount, transaction fee |
| 29 | x+n 8 | Amount, settlement fee |
| 30 | x+n 8 | Amount, transaction processing fee |
| 31 | x+n 8 | Amount, settlement processing fee |
| 32 | n ..11 | Acquiring institution identification code |
| 33 | n ..11 | Forwarding institution identification code |
| 34 | ns ..28 | Primary account number, extended |
| 35 | z ..37 | Track 2 data |
| 36 | n ...104 | Track 3 data |
| 37 | an 12 | Retrieval reference number |
| 38 | an 6 | Authorization identification response |
| 39 | an 2 | Response code |
| 40 | an 3 | Service restriction code |
| 41 | ans 8 | Card acceptor terminal identification |
| 42 | ans 15 | Card acceptor identification code |
| 43 | ans 40 | Card acceptor name/location (1-23 street address, 24-36 city, 37-38 state, 39-40 country) |
| 44 | an ..25 | Additional response data |
| 45 | an ..76 | Track 1 data |
| 46 | an ...999 | Additional data (ISO) |
| 47 | an ...999 | Additional data (national) |
| 48 | an ...999 | Additional data (private) |
| 49 | a or n 3 | Currency code, transaction |
| 50 | a or n 3 | Currency code, settlement |
| 51 | a or n 3 | Currency code, cardholder billing |
| 52 | b 8 | Personal identification number data |
| 53 | n 16 | Security related control information |
| 54 | an ...120 | Additional amounts |
| 55 | ans ...999 | ICC data – EMV having multiple tags |
| 56 | ans ...999 | Reserved (ISO) |
| 57 | ans ...999 | Reserved (national) |
| 58 | ans ...999 | |
| 59 | ans ...999 | |
| 60 | ans ...999 | Reserved (national) (e.g. settlement request: batch number, advice transactions: original transaction amount, batch upload: original MTI plus original RRN plus original STAN, etc) |
| 61 | ans ...999 | Reserved (private) (e.g. CVV2/service code transactions) |
| 62 | ans ...999 | Reserved (private) (e.g. transactions: invoice number, key exchange transactions: TPK key, etc.) |
| 63 | ans ...999 | Reserved (private) |
| 64 | b 16 | Message authentication code (MAC) |
| 65 | b 1 | Extended bitmap indicator |
| 66 | n 1 | Settlement code |
| 67 | n 2 | Extended payment code |
| 68 | n 3 | Receiving institution country code |
| 69 | n 3 | Settlement institution country code |
| 70 | n 3 | Network management information code |
| 71 | n 4 | Message number |
| 72 | n 4 | Last message's number |
| 73 | n 6 | Action date (YYMMDD) |
| 74 | n 10 | Number of credits |
| 75 | n 10 | Credits, reversal number |
| 76 | n 10 | Number of debits |
| 77 | n 10 | Debits, reversal number |
| 78 | n 10 | Transfer number |
| 79 | n 10 | Transfer, reversal number |
| 80 | n 10 | Number of inquiries |
| 81 | n 10 | Number of authorizations |
| 82 | n 12 | Credits, processing fee amount |
| 83 | n 12 | Credits, transaction fee amount |
| 84 | n 12 | Debits, processing fee amount |
| 85 | n 12 | Debits, transaction fee amount |
| 86 | n 16 | Total amount of credits |
| 87 | n 16 | Credits, reversal amount |
| 88 | n 16 | Total amount of debits |
| 89 | n 16 | Debits, reversal amount |
| 90 | n 42 | Original data elements |
| 91 | an 1 | File update code |
| 92 | an 2 | File security code |
| 93 | an 5 | Response indicator |
| 94 | an 7 | Service indicator |
| 95 | an 42 | Replacement amounts |
| 96 | b 64 | Message security code |
| 97 | x+n 16 | Net settlement amount |
| 98 | ans 25 | Payee |
| 99 | n ..11 | Settlement institution identification code |
| 100 | n ..11 | Receiving institution identification code |
| 101 | ans ..17 | File name |
| 102 | ans ..28 | Account identification 1 |
| 103 | ans ..28 | Account identification 2 |
| 104 | ans ...100 | Transaction description |
| 105 | ans ...999 | Reserved for ISO use |
| 106 | ans ...999 | |
| 107 | ans ...999 | |
| 108 | ans ...999 | |
| 109 | ans ...999 | |
| 110 | ans ...999 | |
| 111 | ans ...999 | |
| 112 | ans ...999 | Reserved for national use |
| 113 | ans ...999 | |
| 114 | ans ...999 | |
| 115 | ans ...999 | |
| 116 | ans ...999 | |
| 117 | ans ...999 | |
| 118 | ans ...999 | |
| 119 | ans ...999 | |
| 120 | ans ...999 | Reserved for private use |
| 121 | ans ...999 | |
| 122 | ans ...999 | |
| 123 | ans ...999 | |
| 124 | ans ...999 | |
| 125 | ans ...999 | |
| 126 | ans ...999 | |
| 127 | ans ...999 | |
| 128 | b 64 | Message authentication code |
Processing code
The following is a table specifying the message type and processing code for each transaction type.
| Transaction | Message type | Processing code |
|---|---|---|
| Authorization | 0100 | 00 a0 0x |
| Balance inquiry | 31 a0 0x | |
| Sale | 0200 | 00 a0 0x |
| Cash | 01 a0 0x | |
| Void | 02 a0 0x | |
| Mobile topup | 57 a0 0x |
Response code
The following table shows response codes and their meanings.
| Code | Meaning |
|---|---|
| 00 | Successful approval/completion or that VIP PIN verification is valid |
| 01 | Refer to card issuer |
| 02 | Refer to card issuer, special condition |
| 03 | Invalid merchant or service provider |
| 04 | Pickup |
| 05 | Do not honor |
| 06 | General error |
| 07 | Pickup card, special condition (other than lost/stolen card) |
| 08 | Honor with identification |
| 09 | Request in progress |
| 10 | Partial approval |
| 11 | VIP approval |
| 12 | Invalid transaction |
| 13 | Invalid amount (currency conversion field overflow) or amount exceeds maximum for card program |
| 14 | Invalid account number (no such number) |
| 15 | No such issuer |
| 16 | Insufficient funds |
| 17 | Customer cancellation |
| 19 | Re-enter transaction |
| 20 | Invalid response |
| 21 | No action taken (unable to back out prior transaction) |
| 22 | Suspected Malfunction |
| 25 | Unable to locate record in file, or account number is missing from the inquiry |
| 28 | File is temporarily unavailable |
| 30 | Format error |
| 41 | Merchant should retain card (card reported lost) |
| 43 | Merchant should retain card (card reported stolen) |
| 51 | Insufficient funds |
| 52 | No checking account |
| 53 | No savings account |
| 54 | Expired card |
| 55 | Incorrect PIN |
| 57 | Transaction not permitted to cardholder |
| 58 | Transaction not allowed at terminal |
| 59 | Suspected fraud |
| 61 | Activity amount limit exceeded |
| 62 | Restricted card (for example, in country exclusion table) |
| 63 | Security violation |
| 65 | Activity count limit exceeded |
| 68 | Response received too late |
| 75 | Allowable number of PIN-entry tries exceeded |
| 76 | Unable to locate previous message (no match on retrieval reference number) |
| 77 | Previous message located for a repeat or reversal, but repeat or reversal data are inconsistent with original message |
| 78 | ’Blocked, first used’—The transaction is from a new cardholder, and the card has not been properly unblocked. |
| 80 | Visa transactions: credit issuer unavailable. Private label and check acceptance: Invalid date |
| 81 | PIN cryptographic error found (error found by VIC security module during PIN decryption) |
| 82 | Negative CAM, dCVV, iCVV, or CVV results |
| 83 | Unable to verify PIN |
| 85 | No reason to decline a request for account number verification, address verification, CVV2 verification; or a credit voucher or merchandise return |
| 91 | Issuer unavailable or switch inoperative (STIP not applicable or available for this transaction) |
| 92 | Destination cannot be found for routing |
| 93 | Transaction cannot be completed, violation of law |
| 94 | Duplicate transmission |
| 95 | Reconcile error |
| 96 | System malfunction, System malfunction or certain field error conditions |
| B1 | Surcharge amount not permitted on Visa cards (U.S. acquirers only) |
| N0 | Force STIP |
| N3 | Cash service not available |
| N4 | Cashback request exceeds issuer limit |
| N7 | Decline for CVV2 failure |
| P2 | Invalid biller information |
| P5 | PIN change/unblock request declined |
| P6 | Unsafe PIN |
| Q1 | Card authentication failed |
| R0 | Stop payment order |
| R1 | Revocation of authorization order |
| R3 | Revocation of all authorizations order |
| XA | Forward to issuer |
| XD | Forward to issuer |
| Z3 | Unable to go online |
See also
References
- ↑ ISO 8583-1:2003 Financial transaction card originated messages -- Interchange message specifications -- Part 1: Messages, data elements and code values
- ↑ ISO 8583-2:1998 Financial transaction card originated messages -- Interchange message specifications -- Part 2: Application and registration procedures for Institution Identification Codes (IIC)
- ↑ ISO 8583-3:2003 Financial transaction card originated messages -- Interchange message specifications -- Part 3: Maintenance procedures for messages, data elements and code values
- ↑ MasterCard Customer Interface Specification, 25 July 2017
- ↑ MasterCard Customer Interface Specification, 25 July 2017
