Introduction

What is ISO8583

ISO8583open in new window 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.

ISO8583 Structure

ISO8583 structure is used in Thailand consists of

• Length of Message (2 Bytes)
• TPDU header is 60 (1 Byte)
• Destination Address (2 Bytes)
• Originator Address (2 Bytes)
• Message Type (2 Bytes)
• Bitmap (8 or 16 Bytes)
• Data (N Bytes)

Request Message

Size (hex)	TPDU	Destination Address	Originator Address	Message Type	Bitmap	Data
2 Bytes	1 Byte	2 Bytes	2 Bytes	2 Bytes	8 or 16 Bytes	N Bytes

Response Message

Size (hex)	TPDU	Originator Address	Destination Address	Message Type	Bitmap	Data
2 Bytes	1 Byte	2 Bytes	2 Bytes	2 Bytes	8 or 16 Bytes	N Bytes

ISO8583 Example

[Original Message]
0090600120800002003020058020C800040030000000000010000050740022012000375500000000000001D12112012400403360400F 31313131313131313131313131313131313131313131316042353530313330303037393334383337385E535550415649542050414E594146414E475E3232313132303130303030303030303630343030303030300006303030323337
[Extract Message]
[TPDU] 6001208000
        [MSG_TYPE] 0200
        [BITMAP] 3020058020C80004
                [DE003] 003000
                [DE004] 000000001000
                [DE011] 005074
                [DE022] 0022
                [DE024] 0120
                [DE025] 00
                [DE035] 375500000000000001D12112012400403360400F
                [DE041] 3131313131313131
                [DE042] 313131313131313131313131313131
                [DE045] 6042353530313330303037393334383337385E535550415649542050414E594146414E475E323231313230313030303030303030363034303030303030
                [DE062] 0006303030323337

ISO8583 Message Type

Message Type is type of transaction for tell to host know type of transaction request with the details to follow

The first and second digits identify the class of message

Code	Meaning
01	Authorization message
02	Financial transaction message
03	File Update/Transfer message
04	Reversal message
05	Reconciliation control message
06	Administrative message
08	Network management message

The third and fourth digit identify the message function and transmission mode

Code	Meaning
00	Interactive request
10	Interactive request response
20	Non-Interactive advice
30	Non-Interactive advice response
40	Notification

01xx - Authorization message

Code	Meaning
0100	Authorization request
0110	Authorization response
0120	Authorization advice
0130	Authorization advice response

02xx -Financial transaction message

Code	Meaning
0200	Financial transaction request
0210	Financial transaction response
0220	Financial transaction advice
0230	Financial transaction advice response

03xx - File Update/Transfer message

Code	Meaning
0320	File Update/Transfer advice
0330	File Update/Transfer response

04xx - Reversal message

Code	Meaning
0400	Reversal request
0410	Reversal response

05xx - Reconciliation message

Code	Meaning
0500	Card acceptor reconciliation request
0510	Card acceptor reconciliation response

08xx - Network management message

Code	Meaning
0800	Network management request
0810	Network management response

Bitmap

Bitmap is HEX value to tell data enabled position to can read value at that element position.

How to caluculate bitmap value

• You must know data elements want to use (DE 1 - 64)
• If you know data element want to use. You have to fill out a data in format of binary (0, 1) total 64 bits
• Then convert from Binary to Heximal

Example

Bitmap to want

• HEX : 3020058020C80004
• Decimal: 3,4,11,22,24,25,35,41,42,45,62

1. Initial binary 64 bits.

1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000	0000

2. Replace 1 on 0 according substitute the set values of Decimal at position 1 - 64.

1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
0011	0000	0010	0000	0000	0101	1000	0000	0010	0000	1100	1000	0000	0000	0000	0100

In the example substitute the set values and get 0011 0000 0010 0000 0000 0101 1000 0000 0010 0000 1100 1000 0000 0000 0000 0100

3. Convert Binary to Heximal.

1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
3	0	2	0	0	5	8	0	2	0	C	8	0	0	0	4

In the example substitute the set values and get 3020058020C80004

private fun getBitmap(bitmapData: ArrayList<Int>): String? {
        // Create array list of Int type size of 64
        val bitmap = MutableList<Int?>(64) { 0 }
        // Loop bitmapData
        bitmapData.forEach {
                // Add 1 in bitmap element position
                bitmap[it - 1] = 1
        }
        // Join array list to string and change binary to HEX string
        return utils.binaryToHex(bitmap.joinToString(""))
}