Card processing - common introduction

Introduction

Acquirers and connection

Computop Paygate supports many different credit card connections to various acquirers / processors with different protocols.

You can find an overview of all different credit card interfaces here: Payments by Credit Card.

Additional features (e.g. AVS (Address Verification Service), refund, 3-D Secure, ...) may depend on the specific integration and acquirer.

Integration with Computop Paygate

In general we offer two different ways of integration:

	Payment page (payssl.aspx)	Direct integration (direct.aspx)
Credit card number (PAN) handling	Directly handled by payment page. Credit card number, expiry date, CVV, ... are requested by the payment form You will not get in contact with PAN, so much easier PCI DSS compliance. You will receive optional a PseudoCardNumber (PcNr) as a Computop Paygate internal token to represent the PAN.	Your system handles PAN directly, therefore you have "full control". As your system gets in contact with the credit card number (PAN) your system will be in fully PCI DSS focus.
3-D Secure handling	You only need to add KVP "MsgVer=2.0" to indicate that your system is ready for 3-D Secure 2.x The rest (redirect to issuer bank for consumer authentication) is handled by the Paygate payment page.	You only need to add KVP "MsgVer=2.0" to indicate that your system is ready for 3-D Secure 2.x Your system has to consumer redirect to issuer bank in case of consumer authentication
Additional data	Additional data can be provided via additional JSON parameters, e.g.: "credentialOnFile" (for recurring payments) address data (for AVS) 3-D Secure policy data
Shop-/System integration	The payment page can be customized (logos, colors, positions, ...) to match your corporate identify using templates which can be prepared by you. The consumer is redirectedto the payment page to input credit card details (PAN, expiry date, CVV, ...). Your shop is informed via Paygate notify for result of payment process.	Your system has full control of the input fields for credit card details The consumer is not redirected and your system gets the result of API call via direct response values
Further actions	After initiating the payment process you may start further actions like capture or credit/refund, cancellations, ... These actions refer to a previous payment process identified by a PayId - which is fully out of PCI DSS focus.
Conclusion	Recommended for standard integrations - due to easy integration and simplified compliance. Computop Paygate takes PAN handling for you → simplified PCI DSS handling. You can customize Paygate payment page using templates.	Recommended if you need full control and you do not want a redirect of the consumer. Your system will be in full PCI DSS scope.

The documentation below is therefore always devided into two sections:

integration via payment page (payment form)
- with common parameters to integrate Computop Paygate payment form
- with parameters to customize the payment form
- with specific parameters for the desired acquirer / processor
integration via Server-2-Server (direct) integration
- with common parameters to integrate Computop Paygate payment form
- with specific parameters for the desired acquirer / processor

Implementation of 3-D Secure (2.x)

Common notes to 3-D Secure

3-D Secure is a process that authenticates the card holder to ensure that the consumer using the credit card data really is the card holder.

3-D Secure shall provide abuse of credit card data - specially in ecommerce environment.

3-D Secure 1.x has been implemented and asks the card holder typically for a password with each card usage.

3-D Secure 2.x has been implemented to:

enable strong customer authentication (SCA) by authenticate the card holder with 2 independent factors of these 3 factors:
- something the card holder knows, e.g. a password
- something the card holder owns, e.g. a device (like phone to receive a token via SMS or using other OTP, token generator, ...)
- something the card holder is, e.g. biometrics (like finger print, face-id, ...)
enable seemless authentication where the consumer is not authenticated and not asked to authenticate himself.

3-D Secure with Computop Paygate

Prepare yourself / your integration to be 3-D Secure 2.x ready - here a short overview with some technical details.

3-D Secure 1.x

3-D Secure 2.x

3-D Secure 2.x Sample

Depend on your integration: Payment Form ./. Server-2-Server

Payment Page / Payment Form

Your existing integration.

Just add API parameter "MsgVer=2.0", the rest is handled automatically by Computop Paygate

Add parameter "MsgVer=2.0" to your existing API call to start Payment Form.

URL-processing

URLFailure and URLSuccess work with http-GET

URLFailure and URLSuccess work with http-POST (due to amount of data). So pls. prepare to handle both (GET + POST)

Server-2-Server integration

Use KVP:

CCNr

Credit card number (PAN)

CCExpiry

Expiry date of the credit card

CCCVC

Card verification number

CCBrand

Credit card brand.

Use "card"-JSON to provide card data to API

e.g.:

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{
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    "securityCode": "569",
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    "expiryDate": "202508",
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    "cardholderName": "William Thomas",
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    "number": "4111111111111111",
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    "brand": "VISA"
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}

card=ewogICAgInNlY3VyaXR5Q29kZSI6ICI1NjkiLAogICAgImV4cGlyeURhdGUiOiAiMjAyNTA4IiwKICAgICJjYXJkaG9sZGVyTmFtZSI6ICJXaWxsaWFtIFRob21hcyIsCiAgICAibnVtYmVyIjogIjQxMTExMTExMTExMTExMTEiLAogICAgImJyYW5kIjogIlZJU0EiCn0=

For specific use cases, find other use cases here: 3DS 2.0 Merchant Use-Cases

Use case

3-D Secure 1.x

3-D Secure 2.x

3-D Secure 2.x Sample

Recurring payments (initial)

Use parameter "RTF=I"

you may receive TransactionID as Card scheme specific transaction ID

Change "RTF" to parameter "credentialOnFile"-JSON with "recurring" and "initial=true"

you may receive schemeReferenceID as Card scheme specific transaction ID

e.g.:

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{
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    "type": {
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        "recurring": {
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            "recurringFrequency": 30,
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            "recurringStartDate": "2021-09-14",
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            "recurringExpiryDate": "2022-09-14"
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        }
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    },
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    "initialPayment": true
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}

The JSON needs to be base64-encoded and then used as value for parameter credentialOnFile (pls. be aware to use the full base64-encoded string, including "=" at the end)

credentialOnFile=ewogICAgInR5cGUiOiB7CiAgICAgICAgInJlY3VycmluZyI6IHsKICAgICAgICAgICAgInJlY3VycmluZ0ZyZXF1ZW5jeSI6IDMwLAogICAgICAgICAgICAicmVjdXJyaW5nU3RhcnREYXRlIjogIjIwMjEtMDktMTQiLAogICAgICAgICAgICAicmVjdXJyaW5nRXhwaXJ5RGF0ZSI6ICIyMDIyLTA5LTE0IgogICAgICAgIH0KICAgIH0sCiAgICAiaW5pdGlhbFBheW1lbnQiOiB0cnVlCn0=

Recurring payments (subsequent)

Use parameter "RTF=R"

and send TransactionID as Card scheme specific transaction ID

Change "RTF" to parameter "credentialOnFile"-JSON with "recurring" and "initial=false"

and send schemeReferenceID as Card scheme specific transaction ID

e.g.

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{
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    "type": {
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        "recurring": {
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            "recurringFrequency": 30,
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            "recurringStartDate": "2021-09-14",
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            "recurringExpiryDate": "2022-09-14"
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        }
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    },
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    "initialPayment": false
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}

After base64-encoding:

Customer Initiated (initial)

Use parameter "RTF=E"

you may receive TransactionID as Card scheme specific transaction ID

Change "RTF" to parameter "credentialOnFile"-JSON with with "CIT" and "initial=true"

you may receive schemeReferenceID as Card scheme specific transaction ID

e.g.

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{
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    "type": {
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        "unscheduled": "CIT"
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    },
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    "initialPayment": true
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}

After base64-encoding (again: don't miss "=" at the end; it has to be part of the value):

credentialOnFile=ewogICAgInR5cGUiOiB7CiAgICAgICAgInVuc2NoZWR1bGVkIjogIkNJVCIKICAgIH0sCiAgICAiaW5pdGlhbFBheW1lbnQiOiB0cnVlCn0=

Merchant Initiated (subsequent)

Use parameter "RTF=M"

and send TransactionID as Card scheme specific transaction ID

Change "RTF" to parameter "credentialOnFile"-JSON with with "MIT" and "initial=false"

and send schemeReferenceID as Card scheme specific transaction ID

e.g.

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{
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    "type": {
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        "unscheduled": "MIT"
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    },
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    "initialPayment": false
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}

After base64-encoding:

credentialOnFile=ewogICAgInR5cGUiOiB7CiAgICAgICAgInVuc2NoZWR1bGVkIjogIk1JVCIKICAgIH0sCiAgICAiaW5pdGlhbFBheW1lbnQiOiBmYWxzZQp9

Address Verification Service (AVS)

(depending on acquirer / processor)

Use parameter

AddrStreet
AddrStreetNr
AddrZip
AddrCity
....

Change address data to "address"-JSON

e.g.

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{
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    "city": "New York",
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    "country": {
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        "countryA3": "USA"
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    },
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    "addressLine1": {
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        "street": "Park Avenue",
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        "streetNumber": "270"
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    },
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    "postalCode": "10017-2070",
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    "state": "NY"
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}

billingAddress=ewogICAgImNpdHkiOiAiTmV3IFlvcmsiLAogICAgImNvdW50cnkiOiB7CiAgICAgICAgImNvdW50cnlBMyI6ICJVU0EiCiAgICB9LAogICAgImFkZHJlc3NMaW5lMSI6IHsKICAgICAgICAic3RyZWV0IjogIlBhcmsgQXZlbnVlIiwKICAgICAgICAic3RyZWV0TnVtYmVyIjogIjI3MCIKICAgIH0sCiAgICAicG9zdGFsQ29kZSI6ICIxMDAxNy0yMDcwIiwKICAgICJzdGF0ZSI6ICJOWSIKfQ==

Apply for frictionless payment processing

not supported with 3-D Secure 1.x
each payment will be authenticated

Provide additional data as JSON-KVP: JSON Objects

e.g.:

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{
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    "challengePreference ": "mandateChallenge"
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}

After base64-encoding (again: don't miss "=" at the end; it has to be part of the value):

threeDSPolicy=ewogICAgImNoYWxsZW5nZVByZWZlcmVuY2UgIjogIm1hbmRhdGVDaGFsbGVuZ2UiCn0=