Tokenization for iOS SDK

You can use our Mobile SDK to allow returning customers to process payments on your app without the need to re-enter all of their card details. Not only does this lead to faster and easier payments for your customers, your business also benefits from not needing to store sensitive card numbers (this can simplify your PCI accreditation process).

This process is called Tokenization.

  This document explains how to use an Account check request in order to store the customer’s payment credentials for Tokenization. Account check requests do not debit the customer’s bank account.

But if preferred, tokenization can also be performed on previous Authorisation requests, in which the customer has been charged, providing the requirements specified by the Credentials on File mandate have been met. To do this, you will need the transactionreference of the payment that you would like to repeat, then skip ahead to the Configuration for tokenized payment section of this document, found below.

 

Prerequisites

  • Account Checks are only available for certain acquiring banks. Before you begin, please contact our Support Team and ensure your acquiring bank supports this functionality.
  • Account Checks can only be performed for card-based payment methods.

  In order to reduce fraud, Visa has mandated that all merchants with a Merchant Category Code (MCC) of 6012 are required to send additional fields in AUTH and ACCOUNTCHECK requests. Click here for further information.

 

Process overview

  1. Every transaction can be identified by their transactionreference, a unique identifier assigned by Trust Payments. When a new customer orders from your app, you will need to ensure your own system keeps a record of the transactionreference returned.
  2. Your payment request can include the transactionreference from the customer’s previous purchase – or Account check request – to inherit the card number and expiry date for a new purchase (we explain how to do this, below).
  3. The customer will be prompted to enter the security code that is normally found on the back of their card (because we are unable to store this value on our records for security reasons). The customer will need to enter this in order for additional security checks to be performed by the card issuer.
  4. We will then process the tokenized payment. Ensure your system checks the response JWT to confirm the new payment was processed successfully.

 
Apple Pay does not support tokenization in this manner.

 

Configuration for storing of payment credentials

In order to store the customer’s payment credentials on the Trust Payments system and acquire a reference for use in future purchases, your system can process an Account check using our Mobile SDK.

 

Configure the JWT

You will need to ensure your JWT payload includes the following fields:

Field specification

  Field Format Description
table-required.png credentialsonfile Numeric (1) This must be set to “1”, to indicate the customer agreed for the payment credentials to be stored for future transactions. See below for further information.
table-required.png requesttypedescriptions List This must be set to [“ACCOUNTCHECK”].

  If the credentialsonfile field has been submitted in the request and it is supported by the acquirer processing the transaction, it is returned in the response JWT.

  If the parent response indicates an error occurred (errorcode is not “0”), the credential cannot be considered a stored credential, and you must not use these card details in any subsequent payments.

{
"payload":{
"accounttypedescription":"ECOM",
"baseamount":"1050",
"currencyiso3a":"GBP",
"sitereference":"test_site12345",
"credentialsonfile":"1",
"requesttypedescriptions":["ACCOUNTCHECK"]
},
"iat":1559033849,
"iss":"jwt.user"
}

 

About Credentials on File

 stored credential is information (including, but not limited to, an account number or payment token) that is stored in order to process future transactions.

The process of storing credentials for future use is known as Credentials on File (CoF).

  Visa and Mastercard have mandated that you must obtain cardholder consent before storing card details for future use, and that these must be flagged at the time of the first authorisation, by submitting the credentialsonfile field in your requests. You must also flag any subsequent payments that are utilising previously-stored credentials, by including the credentialsonfile field in these requests.

Identifying transactions as using CoF provides the following advantages:

  • Increases the likelihood of transaction authorisation and settlement.
  • Greater transparency and improved experience from the customer’s perspective.
  • Issuers are less likely to use the absence of a security code as a reason to decline a transaction.

Handling the response

After the request has been processed, you will receive a single response JWT that contains the response to the ACCOUNTCHECK request:

  Every JWT returned from the SDK should be verified before continuing. We provide a parsing utility that makes it easier to convert the JWT to a transaction response object. Click here for an example on how to use this.

  • Ensure that the errorcode value returned is “0”, indicating success. (You must not store credentials if an error has occurred)
  • Check the values returned in the securityresponseaddress, securityresponsepostcode and securityresponsesecuritycode fields. Click here for further information on these checks and only proceed if business requirements have been satisfied.

Following successful tokenization, you can store the transactionreference in your records. This will be needed later in order to process a new payment with the stored payment credentials. You can also store the last four digits of the maskedpan and paymenttypedescription for purposes of displaying to returning customers when they are choosing their payment method for their next purchase.

 

Configuration for tokenized payment

Here is an example of a drop-in view controller with only the security code field visible, in order to perform a transaction using the payment credentials referenced by a transactionreference stored on your server:

let visibleFields = CardType.cardType(for: cardReference.cardType) == .amex ? [DropInViewVisibleFields.cvv4] : [.cvv3]

let dropInViewController = try ViewControllerFactory.shared.dropInViewController(jwt: jwt, visibleFields: visibleFields, payButtonTappedClosureBeforeTransaction: {
controller in
controller.continue()
}, transactionResponseClosure: { _, _, _ in })

 

Configure the JWT

You will also need to ensure your JWT payload includes the following fields:

 

Field specification

  Field Format Description
table-required.png credentialsonfile Numeric (1) This must be set to “2”, to indicate the new transaction is using previously-stored credentials.
table-required.png parenttransactionreference Alphanumeric
& hyphens (25)
Submit the transaction reference of the previous request from which the card details will be inherited.

table-required.png

requesttypedescriptions List

This will need to contain at least the following request types:
[“THREEDQUERY”,”AUTH”]

Click here to learn more.

(Payload)

{
"payload":{
"accounttypedescription":"ECOM",
"baseamount":"1050",
"currencyiso3a":"GBP",
"sitereference":"test_site12345",
"parenttransactionreference":"1-2-345",
"credentialsonfile":"2",
"termurl":"https://payments.securetrading.net/process/payments/mobilesdklistener",
"requesttypedescriptions":["THREEDQUERY","AUTH"]
},
"iat":1559033849,
"iss":"jwt.user"
}

 

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