Securing Requests

Trustly secures requests by proving a hash of data using your accessKey as part of the input.

Create a Request Signature

Secure your request by adding a requestSignature to the input parameters passed to the SDK request.

Create a Request Signature

const generateSignature = (establishData, accessKey) => {
  let query = '';
  query += `accessId=${establishData.accessId}`;
  query += `&merchantId=${establishData.merchantId}`;
  query += `&description=${establishData.description}`;
  query += `&currency=${establishData.currency}`;
  query += `&amount=${establishData.amount}`;
  query += `&displayAmount=${establishData.displayAmount}`;
  query += `&minimumBalance=${establishData.minimumBalance}`;
  query += `&merchantReference=${establishData.merchantReference}`;
  query += `&paymentType=${establishData.paymentType}`;
  query += `&timeZone=${establishData.timeZone}`;

  if (establishData.paymentType === 'Recurring' && establishData.recurrence) {
    if (establishData.recurrence.startDate) query += `&recurrence.startDate=${establishData.recurrence.startDate}`;
    if (establishData.recurrence.endDate) query += `&recurrence.endDate=${establishData.recurrence.endDate}`;
    if (establishData.recurrence.frequency) query += `&recurrence.frequency=${establishData.recurrence.frequency}`;
    if (establishData.recurrence.frequencyUnit) query += `&recurrence.frequencyUnit=${establishData.recurrence.frequencyUnit}`;
    if (establishData.recurrence.frequencyUnitType) query += `&recurrence.frequencyUnitType=${establishData.recurrence.frequencyUnitType}`;
    if (establishData.recurrence.recurringAmount) query += `&recurrence.recurringAmount=${establishData.recurrence.recurringAmount}`;
    if (establishData.recurrence.automaticCapture) query += `&recurrence.automaticCapture=${establishData.recurrence.automaticCapture}`;
  }

  if (establishData.verification) {
    if (establishData.verification.status) query += `&verification.status=${establishData.verification.status}`;
    if (establishData.verification.verifyCustomer) query += `&verification.verifyCustomer=${establishData.verification.verifyCustomer}`;
  }

  if (establishData.customer) {
    if (establishData.customer.customerId) query += `&customer.customerId=${establishData.customer.customerId}`;
    if (establishData.customer.externalId) query += `&customer.externalId=${establishData.customer.externalId}`;
    if (establishData.customer.name) query += `&customer.name=${establishData.customer.name}`;
    if (establishData.customer.vip !== undefined) query += `&customer.vip=${establishData.customer.vip}`;
    if (establishData.customer.taxId) query += `&customer.taxId=${establishData.customer.taxId}`;
    if (establishData.customer.driverLicense) {
      if (establishData.customer.driverLicense.number) query += `&customer.driverLicense.number=${establishData.customer.driverLicense.number}`;
      if (establishData.customer.driverLicense.state) query += `&customer.driverLicense.state=${establishData.customer.driverLicense.state}`;
    }
    if (establishData.customer.address) {
      if (establishData.customer.address.address1) query += `&customer.address.address1=${establishData.customer.address.address1}`;
      if (establishData.customer.address.address2) query += `&customer.address.address2=${establishData.customer.address.address2}`;
      if (establishData.customer.address.city) query += `&customer.address.city=${establishData.customer.address.city}`;
      if (establishData.customer.address.state) query += `&customer.address.state=${establishData.customer.address.state}`;
      if (establishData.customer.address.zip) query += `&customer.address.zip=${establishData.customer.address.zip}`;
      if (establishData.customer.address.country) query += `&customer.address.country=${establishData.customer.address.country}`;
    }
    if (establishData.customer.phone) query += `&customer.phone=${establishData.customer.phone}`;
    if (establishData.customer.email) query += `&customer.email=${establishData.customer.email}`;
    if (establishData.customer.balance) query += `&customer.balance=${establishData.customer.balance}`;
    if (establishData.customer.currency) query += `&customer.currency=${establishData.customer.currency}`;
    if (establishData.customer.enrollDate) query += `&customer.enrollDate=${establishData.customer.enrollDate}`;
  }

  if (establishData.account) {
    if (establishData.account.nameOnAccount) query += `&account.nameOnAccount=${establishData.account.nameOnAccount}`;
    if (establishData.account.name) query += `&account.name=${establishData.account.name}`;
    if (establishData.account.type) query += `&account.type=${establishData.account.type}`;
    if (establishData.account.profile) query += `&account.profile=${establishData.account.profile}`;
    if (establishData.account.accountNumber) query += `&account.accountNumber=${establishData.account.accountNumber}`;
    if (establishData.account.routingNumber) query += `&account.routingNumber=${establishData.account.routingNumber}`;
  }

  if (establishData.transactionId) query += `&transactionId=${establishData.transactionId}`;

  const requestSignature = Crypto.createHmac('sha1', accessKey).update(query).digest('base64');
  return requestSignature;
}
public class TrustlySignature {

  public static class Account { //Used only on account verification
    public String nameOnAccount;
    public String name;
    public String type;
    public String profile;
    public String accountNumber;
    public String routingNumber;
  }

  public static class Recurrence { //Used only when payment type is Recurring
    public Date startDate;
    public Date endDate;
    public Integer frequency;
    public Integer frequencyUnit;
    public Integer frequencyUnitType;
    public BigDecimal recurringAmount;
    public Boolean automaticCapture;
  }

  public static class Address {
    public String address1;
    public String address2;
    public String city;
    public String state;
    public String zip;
    public String country;
  }

  public static class DriverLicense {
    public String number;
    public String state;
  }

  public static class Customer {
    public String customerId; //Trustly's customer ID
    public String externalId; //Merchant’s customer ID
    public String name;
    public String vip;
    public String taxId;
    public DriverLicense dl;
    public Address address;
    public String phone;
    public String email;
    public String currency;
    public String enrollDate;
  }

  public static class Verification {
    public String status;
    public Boolean verifyCustomer;
  }

  public String createRequestSignature(String accessId,
                                       String accessKey,
                                       String merchantId,
                                       String description,
                                       String currency,
                                       BigDecimal amount,
                                       BigDecimal displayAmount,
                                       BigDecimal minimumBalance,
                                       String merchantReference,
                                       String paymentType,
                                       String timeZone,
                                       Recurrence r,
                                       Verification v,
                                       Customer c,
                                       Account a,
                                       String transactionId) throws Exception {
    String str = "accessId="+ accessId;
    if(merchantId != null) str += "&merchantId="+merchantId;
    if(description != null) str += "&description="+description;
    if(currency != null) str += "&currency="+currency;
    if(amount != null) str += "&amount="+amount.setScale(2); //2 decimal places such as 13.25
    if(displayAmount != null) str += "&displayAmount="+displayAmount.setScale(2); //2 decimal places such as 13.25
    if(minimumBalance != null) str += "&minimumBalance="+minimumBalance.setScale(2); //2 decimal places such as 13.25
    if(merchantReference != null) str += "&merchantReference="+merchantReference;
    if(paymentType != null) str += "&paymentType="+paymentType;
    if(timeZone != null) str += "&timeZone="+timeZone;

    if("Recurring".equals(paymentType) && r != null){
      if(r.startDate != null) str += "&recurrence.startDate=" + r.startDate.getTime();
      if(r.endDate != null) str += "&recurrence.endDate=" + r.endDate.getTime();
      if(r.frequency != null) str += "&recurrence.frequency="+r.frequency;
      if(r.frequencyUnit != null) str += "&recurrence.frequencyUnit="+r.frequencyUnit;
      if(r.frequencyUnitType != null) str +="&recurrence.frequencyUnitType="+r.frequencyUnitType;
      if(r.recurringAmount != null) str +="&recurrence.recurringAmount="+r.recurringAmount;
      if(r.automaticCapture != null) str +="&recurrence.automaticCapture="+r.automaticCapture;
    }

    if (v != null) {
      if(v.status != null) str +="&verification.status=" + v.status;
      if(v.verifyCustomer != null) str +="&verification.verifyCustomer=" + v.verifyCustomer;      
    }

    if(c != null) {
      if(c.customerId != null) str +="&customer.customerId=" + c.customerId;
      if(c.externalId != null) str +="&customer.externalId=" + c.externalId;
      if(c.name != null) str +="&customer.name=" + c.name;
      if(c.vip != null) str +="&customer.vip=" + c.vip;
      if(c.taxId != null) str +="&customer.taxId=" + c.taxId;

      if(c.dL != null) {
          if(c.dL.number != null) str +="&customer.driverLicense.number=" + c.dL.number;
        if(c.dL.state != null) str +="&customer.driverLicense.state=" + c.dL.state;
      }

      if(c.address != null) {
        if(c.address.address1 != null) str +="&customer.address.address1=" + c.address.address1;
        if(c.address.address2 != null) str +="&customer.address.address2=" + c.address.address2;
        if(c.address.city != null) str +="&customer.address.city=" + c.address.city;
        if(c.address.state != null) str +="&customer.address.state=" + c.address.state;
        if(c.address.zip != null) str +="&customer.address.zip=" + c.address.zip;
        if(c.address.country != null) str +="&customer.address.country=" + c.address.country;
      }
      if(c.phone != null) str +="&customer.phone=" + c.phone;
      if(c.email != null) str +="&customer.email=" + c.email;
      if(c.balance != null) str +="&customer.balance=" + c.balance.setScale(2);      
      if(c.currency != null) str +="&customer.currency=" + c.currency;
      if(c.enrollDate != null) str +="&customer.enrollDate=" + c.enrollDate;
    }

    if(a != null) {
      if(a.nameOnAccount != null) str +="account.nameOnAccount=" + a.nameOnAccount;
      if(a.name != null) str +="account.name=" + a.name;
      if(a.type != null) str +="account.type=" + a.type;
      if(a.accountNumber!= null) str +="account.accountNumber=" + a.accountNumber;
      if(a.routingNumber!= null) str +="account.routingNumber=" + a.routingNumber;
    }

    if(transactionId != null) str += "&transactionId="+transactionId;

    return TrustlySignature.doHashing(str,accessKey);
  }

  public static String doHashing(String str, String accessKey) throws Exception {
    Mac = Mac.getInstance("HmacSHA1");
    SecretKeySpec signingKey = new SecretKeySpec(accessKey.getBytes(),"HmacSHA1");
    mac.init(signingKey);
    byte[] rawHmac = mac.doFinal(str.getBytes());
    return encodeBase64(rawHmac);
  }

  public static String encodeBase64(byte[] binary){
    return DatatypeConverter.printBase64Binary(binary);
  }
}

The requestSignature is a server-side generated HMAC-SHA1 hash of the payment parameters, using the provided accessKey, which ensures the payment data used in the SDK call on the merchant page has not been tampered with.

To create a requestSignature, follow these steps:

  1. Flatten the JSON request to a string.
  2. Using your accessKey and the flattened string, calculate the signature and generate a Base64 encoded HMAC-SHA1 hash.
  3. Add the encoded string as the value of the requestSignature parameter in your request.

When creating your request, the fields must be in the following order.

  • accessId
  • merchantId
  • description
  • currency
  • amount
  • displayAmount
  • minimumBalance
  • merchantReference
  • paymentType
  • timeZone
  • recurrence.startDate
  • recurrence.endDate
  • recurrence.frequency
  • recurrence.frequencyUnit
  • recurrence.frequencyUnitType
  • recurrence.recurringAmount
  • recurrence.automaticCapture
  • verification.status
  • verification.verifyCustomer
  • customer.customerId
  • customer.externalId
  • customer.name
  • customer.vip
  • customer.taxId
  • customer.driverLicense.number
  • customer.driverLicense.state
  • customer.address.address1
  • customer.address.address2
  • customer.address.city
  • customer.address.state
  • customer.address.zip
  • customer.address.country
  • customer.phone
  • customer.email
  • customer.balance
  • customer.currency
  • customer.enrollDate
  • account.nameOnAccount
  • account.name
  • account.type
  • account.profile
  • account.accountNumber
  • account.routingNumber
  • transactionId

Validate the Redirect Signature

You can check the validity of the Trustly Redirect by calculating the requestSignature and comparing it to the passed value.

To calculate a requestSignature, follow these steps:

Given the following returnUrl:

https://merchant.com/Trustly/return?transactionId=1002655801&transactionType=1&merchantReference=123123&status=2&payment.paymentType=4&payment.paymentProvider.type=1&payment.account.verified=false&panel=1&requestSignature=2uvoRTIEFWzfsbZwXokudh5P5rs%3D&instantPayoutAvail=true

1. Remove the requestSignature parameter (including &) and it's value from the string.

https://merchant.com/Trustly/return?transactionId=1002655801&transactionType=1&merchantReference=123123&status=2&payment.paymentType=4&payment.paymentProvider.type=1&payment.account.verified=false&panel=1

2. Using your accessKey, calculate the signature and generate a Base64 encoded HMAC-SHA1 hash.

2uvoRTIEFWzfsbZwXokudh5P5rs=

3. Compare the calculated hash (2uvoRTIEFWzfsbZwXokudh5P5rs=) to the decoded hash that was passed in the query string (2uvoRTIEFWzfsbZwXokudh5P5rs=).

Validate the Notification Signature

Validate the Notification Signature

const isValidSignature = (request, header, apiKey) => {
  // decodeURIComponent doesn't properly decode '+' to ' '.
  const test = Crypto.createHmac('sha1', apiKey).update(decodeURIComponent(request).replace(/\+/g, ' ')).digest('base64');
  const auth = Buffer.from(authHeader, 'base64').toString('utf8').split(':');
  return test === auth[1];
}

The request signature is calculated as a HMAC-SHA1 of the request parameters using accessKey as the signing key. To calculate, follow these steps:

1. Read the entire POST request body.

merchantId=1002463580&merchantReference=cb180040-7210-4ab9-97b7-415824754802&paymentType=2&transactionType=3&eventId=1002593570&eventType=Authorize&objectId=1002593555&objectType=Transaction&message=&timeZone=Etc%2FUTC&createdAt=1556234040954&accessId=M8RaHgEjBE54zuFYMRQq&paymentProviderTransaction.status=AC100&paymentProviderTransaction.statusMessage=AC100&status=2&statusMessage=Authorized

2. Decode the string using UTF-8.

merchantId=1002463580&merchantReference=cb180040-7210-4ab9-97b7-415824754802&paymentType=2&transactionType=3&eventId=1002593570&eventType=Authorize&objectId=1002593555&objectType=Transaction&message=&timeZone=Etc/UTC&createdAt=1556234040954&accessId=M8RaHgEjBE54zuFYMRQq&paymentProviderTransaction.status=AC100&paymentProviderTransaction.statusMessage=AC100&status=2&statusMessage=Authorized

3. Using your accessKey, calculate the signature and generate a Base64 encoded HMAC-SHA1 hash.

EYN3GXasrVU1vQ1uyYz22NNQdy4=

4. Grab the Authorization header and remove the Basic prefix.

TThSYUhnRWpCRTU0enVGWU1SUXE6RVlOM0dYYXNyVlUxdlExdXlZejIyTk5RZHk0PQ==

5. Decode the Base64 string to get a accessId:signature string.

M8RaHgEjBE54zuFYMRQq:EYN3GXasrVU1vQ1uyYz22NNQdy4=

6. Split the decoded string on the : to the get the signature.

EYN3GXasrVU1vQ1uyYz22NNQdy4=

  1. Compare the values calculated in Steps 3 (EYN3GXasrVU1vQ1uyYz22NNQdy4=) and 6 (EYN3GXasrVU1vQ1uyYz22NNQdy4=). If they match, the request is valid. If they do not match and the failures continue for a long period of time, contact Trustly.

You can use the example Header and Request above, with an accessKey of vMBWAvMXdPM27F9qZEkr to confirm your signature verification code is working properly.

Encrypt a field value

const Crypto = require('crypto');

const accessKey = 'YOUR_ACCESS_KEY';
const attributeValue = '123123456';

const algorithm = 'aes-256-cbc';
const encoding = 'base64';

const iv = Buffer.from(Crypto.randomBytes(16)).toString('hex').slice(0, 16);;

const keyHash = Crypto.createHash('sha256').update(accessKey).digest();

const cipher = Crypto.createCipheriv(algorithm, keyHash.slice(0, 32), iv);
cipher.setAutoPadding(true);

let encrypted = cipher.update(iv + attributeValue, 'utf8', encoding);
encrypted += cipher.final(encoding);

console.log('response', 'crypt2:' + encrypted);
public class EncryptedAttribute {
    public static final String AES_ECB_PKCS_5_PADDING = "AES/ECB/PKCS5Padding";
    private static volatile SecureRandom numberGenerator = new SecureRandom();
    public static byte[] salt(byte[] data) {
        byte[] salt = new byte[4];
        numberGenerator.nextBytes(salt);
        byte[] salted = new byte[data.length + salt.length];
        System.arraycopy(salt, 0, salted, 0, salt.length);
        System.arraycopy(data, 0, salted, salt.length, data.length);
        return salted;
    }
    public static byte[] unsalt(byte[] data) {
        byte[] unsalted = new byte[data.length - 4];
        System.arraycopy(data, 4, unsalted, 0, unsalted.length);
        return unsalted;
    }
    public static String encodeBase64(byte[] binary) {
        return Base64.getEncoder().encodeToString(binary);
    }
    public static byte[] decodeBase64(String str) {
        try {
            return Base64.getDecoder().decode(str);
        } catch (Exception e) {
            return new byte[0];
        }
    }
    public static String encryptAttribute(String attribute, String accessKey) throws Exception {
        if (attribute == null || attribute.length() == 0) {
            return attribute;
        }
        Cipher cipher = Cipher.getInstance(AES_ECB_PKCS_5_PADDING);
        cipher.init(Cipher.ENCRYPT_MODE, buildKey(accessKey));
        return "crypt:" + encodeBase64(cipher.doFinal(salt(attribute.getBytes("UTF-8"))));
    }
    public static String decryptAttribute(String attribute, String accessKey) {
        if (attribute == null || accessKey == null || !attribute.startsWith("crypt:")) { //If attribute is not
            encrypted
            return it
            return attribute;
        }
        try {
            Cipher cipher = Cipher.getInstance(AES_ECB_PKCS_5_PADDING);
            cipher.init(Cipher.DECRYPT_MODE, buildKey(accessKey));
            return new String(unsalt(cipher.doFinal(decodeBase64(attribute.substring("crypt:".length())))), "UTF-
                8 ");
            }
            catch (Exception e) {
                return attribute;
            }
        }
        private static SecretKeySpec buildKey(String accessKey) throws Exception {
            MessageDigest digester = MessageDigest.getInstance("SHA-1");
            digester.update(accessKey.getBytes("UTF-8"));
            byte[] key = Arrays.copyOf(digester.digest(), 16);
            SecretKeySpec spec = new SecretKeySpec(key, "AES");
            return spec;
        }
    }
using System;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

public class Program
{
    public static void Main()
    {
        const string accessKey = "YOUR_ACCESS_KEY";
        const string attributeValue = "123123456";

        var random = new Byte[16];
        RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
        rng.GetBytes(random);
        var iv = BitConverter.ToString(random).Replace("-", "").Substring(0, 16);
        
        var keyHash = SHA256.Create().ComputeHash(Encoding.UTF8.GetBytes(accessKey));
        
        Aes aes = Aes.Create();
        aes.Key = keyHash;
        aes.IV = UTF8Encoding.UTF8.GetBytes(iv);
        aes.Mode = CipherMode.CBC;
        ICryptoTransform cipher = aes.CreateEncryptor(aes.Key, aes.IV);
        
        var inputBuffer = aes.IV.Concat(UTF8Encoding.UTF8.GetBytes(attributeValue)).ToArray();
        var resultArray = cipher.TransformFinalBlock(inputBuffer, 0, inputBuffer.Length);
        
        var encrypted = Convert.ToBase64String(resultArray, 0, resultArray.Length);
        Console.WriteLine("crypt2:" + encrypted);
    }
}

It is possible to encrypt the attributes sent on the establish data object to Trustly. The encryption is done using the AES-256-CBC algorithm and the accessKey as the encryption key. The encrypted attributes start with the prefix “crypt2:” and the full encrypted value (including the prefix) must be used when calculating the request signature.

1. Create an initialization vector (iv) containing 16 random characters.

2. Create a SHA256 hash of your accessKey.

3. Using the first 32 characters of your accessKey hash (from step 2) and the initialization vector (from step 1), create a cipher.

4. Using the cipher key (from step 3), the initialization vector (from step 1), and the attribute value to encrypt, update the cipher.

5. Create an encrypted string by finalizing the cipher using base64 encoding.

6. Concatenate crypt2: and your encrypted string, and pass the value in the establishData value that is passed to the SDK:

customer: {
  name: 'John Smith',
  taxId: 'crypt2:uFVg4qGHj7ZtwSv1tkFAL7pBJ5x8zsehYgNdU51w5yA=',
  address: {
    country: 'US',
  }
},

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