Integrating 1C-Bitrix with PriorBank Internet Acquiring in Belarus

Integrating 1C-Bitrix with PriorBank acquiring in Belarus is a tricky task. The Computop Paygate payment gateway uses Blowfish encryption, not the familiar JSON REST API. An error in the algorithm leads to an empty response without any message, making it hard to find the cause. Our team has connected over 50 projects over 8 years, so we know every nuance. Below is a practical code guide that will save you days of debugging.

How the parameter encryption algorithm works

PriorBank uses Computop Paygate (paygate.computop.com). All request parameters are encrypted with the Blowfish algorithm in ECB mode with padding to a multiple of 8 bytes and then Base64-encoded. Additionally, HMAC-MD5 is computed for verification. This approach is fundamentally different from modern REST APIs, where data is sent in plain text or with JWT. Blowfish is faster than AES on older processors but requires strict key length compliance (up to 56 bytes). A one-byte key error results in an empty gateway response with no diagnostics.

Why URLNotify must be publicly accessible

Computop sends POST notifications to URLNotify only if the server is reachable from the internet. This is a problem for local development—localhost won't work. The solution is ngrok, which creates a temporary external URL. If notifications are not received, check that the link is not blocked by a firewall. In production, 99.9% of notifications are delivered within 1-2 seconds.

Step-by-step handler setup in Bitrix

1. Create a payment system handler in /bitrix/tools/sale_ps_result.php.
2. Obtain MerchantID, Blowfish key, and HMAC key from the bank.
3. Implement the ComputopCipher class (see listing below).
4. Generate an HTML payment form with fields MerchantID, Len, and Data.
5. Process notifications: decrypt Data, verify MAC, update order status.
6. Test in the test environment with provided test cards.
7. Switch to the production MerchantID and verify the payment.

Technical architecture and encryption

The PriorBank payment gateway is technically based on Computop Paygate. Key features:

• Parameters are transmitted encrypted — Blowfish (ECB) + Base64, plus HMAC-MD5 for verification
• The payment form redirects to the Computop page, not hosted-fields
• Notifications are synchronous via URLNotify (POST on status change) and parameters in URLSuccess/URLFailure

This integration fundamentally differs from common JSON REST APIs: all parameters are encrypted, and an encryption algorithm error results in an empty response without a clear error message.

class ComputopCipher
{
    private string $blowfishKey;
    private string $merchantId;
    private string $hmacKey;

    public function __construct(string $merchantId, string $blowfishKey, string $hmacKey)
    {
        $this->merchantId = $merchantId;
        $this->blowfishKey = $blowfishKey;
        $this->hmacKey = $hmacKey;
    }

    public function encrypt(array $params): string
    {
        $queryString = http_build_query($params);
        $len = strlen($queryString);

        // Pad to multiple of 8 bytes (Blowfish ECB requirement)
        $pad = (8 - ($len % 8)) % 8;
        $queryString = str_pad($queryString, $len + $pad, "\0");

        $encrypted = openssl_encrypt(
            $queryString,
            'BF-ECB',
            $this->blowfishKey,
            OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING
        );

        return base64_encode($encrypted);
    }

    public function decrypt(string $data): array
    {
        $decrypted = openssl_decrypt(
            base64_decode($data),
            'BF-ECB',
            $this->blowfishKey,
            OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING
        );
        parse_str(rtrim($decrypted, "\0"), $result);
        return $result;
    }

    public function getHmac(array $params): string
    {
        $data = implode('*', [
            $params['PayID'] ?? '',
            $params['TransID'] ?? '',
            $this->merchantId,
            $params['Amount'] ?? '',
            $params['Currency'] ?? '',
        ]);
        return hash_hmac('md5', $data, $this->hmacKey);
    }
}

Generating the payment form

$cipher = new ComputopCipher($merchantId, $blowfishKey, $hmacKey);

$params = [
    'MerchantID' => $merchantId,
    'TransID'    => 'ORDER_' . $orderId . '_' . time(),
    'Amount'     => (int)($orderAmount * 100),  // in minor units
    'Currency'   => 'BYN',
    'OrderDesc'  => 'Order No. ' . $orderId,
    'URLSuccess' => 'https://myshop.by/checkout/success/?order=' . $orderId,
    'URLFailure' => 'https://myshop.by/checkout/fail/?order=' . $orderId,
    'URLNotify'  => 'https://myshop.by/bitrix/tools/sale_ps_result.php',
    'Language'   => 'ru',
    'MAC'        => $cipher->getHmac(['TransID' => 'ORDER_'.$orderId.'_'.time(), 'Amount' => (int)($orderAmount*100), 'Currency' => 'BYN']),
];

$encryptedData = $cipher->encrypt($params);
$len = strlen(http_build_query($params));

HTML form for redirect:

<form method="POST" action="https://paygate.computop.com/pay/">
    <input type="hidden" name="MerchantID" value="<?= $merchantId ?>">
    <input type="hidden" name="Len" value="<?= $len ?>">
    <input type="hidden" name="Data" value="<?= htmlspecialchars($encryptedData) ?>">
    <button type="submit">Pay</button>
</form>

Processing notifications

Computop sends a POST to URLNotify with encrypted Data and Len:

// In the handler /bitrix/tools/sale_ps_result.php

$encryptedData = $_POST['Data'] ?? '';
$len = (int)($_POST['Len'] ?? 0);

$decrypted = $cipher->decrypt($encryptedData);
parse_str(substr(http_build_query($decrypted), 0, $len), $params);

// Always verify MAC
$expectedMac = $cipher->getHmac($params);
if (!hash_equals($expectedMac, $params['MAC'] ?? '')) {
    http_response_code(403);
    exit('Invalid MAC');
}

// Success codes
if (($params['Code'] ?? '') === '00000000') {
    $payment->setPaid('Y');
    $payment->setField('PS_STATUS_CODE', $params['Code']);
    $payment->setField('PS_STATUS_MESSAGE', $params['Description'] ?? '');
    $payment->save();
}

Common Computop/PriorBank response codes:

Test environment

PriorBank provides a test MerchantID and test BlowfishKey. Computop test cards:

• VISA: 4200000000000000 — successful payment
• Mastercard: 5500000000000004 — successful payment
• Any card with Expiry = 1200 — decline

Important testing nuance: URLNotify must be reachable from Computop servers — localhost won't work. Use ngrok or a temporary public URL for local development.

Particularities for Belarus

• Payment currency is BYN (Belarusian ruble), ISO code 974
• Amount is passed in minor currency units (e.g., kopecks for BYN)
• For Belkart cards, a separate connection via Belkart protocol is needed — different from Computop
• Bank operating day is working days; settlements are next banking day
• Time savings on manual processing — up to 30% due to automatic fiscalization (via ATOL or SBIS)

What's included and timelines

We prepare full integration documentation, configure the payment system handler in Bitrix, set up URLNotify, perform testing in the test environment, and assist with production connection. We also train your team on basic administration. All work is delivered turnkey within 5–7 business days.

For an exact cost and timeline estimate, contact us — we'll evaluate your project individually. We guarantee post-launch support for one month. Order the integration, and we'll set up acquiring turnkey. Get a consultation: we'll answer any integration questions.

Computop Paygate API Reference — detailed parameter and error code description is available in the official documentation.

Blowfish (cipher) — Wikipedia HMAC — Wikipedia

How can you avoid typical mistakes when connecting payment systems on 1C-Bitrix?

The most common mistake during integration is forgetting about the callback. The customer paid for the order, the money was debited, but the status in b_sale_order did not update: the manager sees "Awaiting payment" and starts calling the client. The reason is an incorrect URL in the gateway settings or a handler that returns a 500 error for an atypical response structure. We offer services for connecting payment systems on 1C-Bitrix with full testing of all scenarios: successful payment, refusal, timeout, partial refund, duplicate callback.

Why are callbacks critical?

Each payment gateway sends a notification to your server. If the handler does not guarantee idempotency, a double call will lead to a double charge. We always implement a check by notification ID (external_id) and block repeated processing in \Bitrix\Sale\Order. It is also critical to set the callback URL in the aggregator's personal account – /bitrix/tools/sale_ps_result.php for the standard module. If you use a custom handler, we verify that it returns HTTP 200 even in case of parameter errors (the gateway should not repeat the request indefinitely).

use Bitrix\Sale\Order;
use Bitrix\Main\Application;

// Get notification data
$data = Application::getInstance()->getContext()->getRequest()->toArray();
// Check signature (depends on aggregator)
if (!checkSignature($data, 'SECRET_KEY')) {
    die('FAIL');
}
// Find order by external ID
$order = Order::loadByExternalId((int)$data['order_number']);
if ($order && $order->isPaid() === false) {
    $order->setField('PAYED', 'Y');
    $order->save();
}
echo 'OK';

How do we optimize payment flow for higher conversion?

How to choose a payment aggregator for 1C-Bitrix?

The choice of aggregator depends on the geography of customers, average order value, and need for installments. For Russia, the basic set is YooKassa (all main methods, fiscalization out of the box) and CloudPayments (widget on the page without redirect, Apple Pay). If you work with large corporate clients, add Sberbank (SberPay, SBP). For international sales, use Stripe or PayPal. We often use a two-tier scheme: main aggregator + backup (auto-switching on failure).

What payment gateways and methods do we use?

YooKassa

One contract – all main methods: Visa/MasterCard/MIR cards, YooMoney, SberPay, internet banking, installments. Fiscalization under 54-FZ out of the box (via the sale module). The standard handler /bitrix/modules/sale/handlers/paysystem/yandexpay/ covers basic scenarios. For holding (two-stage payment), subscriptions, or split payments, custom integration via YooKassa API v3. Callback is configured to /bitrix/tools/sale_ps_result.php, we parse notification and update \Bitrix\Sale\Order via setField('PAYED', 'Y').

CloudPayments

Focused on conversion: the payment widget directly on the checkout page, without redirect to an external domain. The customer does not leave the site – the abandonment rate during payment drops. It supports recurring payments (card tokenization via cryptogram), Apple Pay, and Google Pay. 3D Secure with intelligent routing – requested only for high fraud risk. Integration with Bitrix – via CloudPayments REST API and a custom handler in the sale module.

Tinkoff Payment

API integration via TinkoffPaymentAPI (ready-made module or manual implementation). QR code for payment via the app, "Tinkoff Credit" installment – critical for expensive goods. Partial refunds via the Cancel method – without calling the bank, everything from the Bitrix admin panel.

Sberbank (SberPay and SBP)

SberPay – payment via push notification or QR, SBP – commission 0.4–0.7% vs 1.5–2.5% for cards. This is a significant savings on volume. Holding via registerPreAuth / deposit API. Note that SberPay requires a separate agreement with the bank.

Apple Pay and Google Pay

Payment in two clicks, without entering card data. They are connected through an aggregator (YooKassa, CloudPayments, Tinkoff). Important nuances:

• Apple Pay requires domain verification: the file apple-developer-merchantid-domain-association in /.well-known/. Without it, the button will not appear.
• Button placement strictly according to Apple and Google guidelines – otherwise rejection in review.
• Fallback to the standard payment form if the device does not support contactless payment.

How do we handle installments, BNPL, and 54-FZ compliance?

If the average order value is above 30,000 RUB and conversion drops, installment removes the price barrier. We connect:

• Tinkoff Installment (3–24 months)
• Buy with Sber
• Mokka / Dolyami – BNPL: 4 payments, 0% for the buyer

Integration: widget with monthly payment calculation on the product card ("from 2,500 RUB/month"), order data transfer to the bank via API, status processing (approval, rejection, awaiting documents) in OnSaleStatusOrder handlers.

Fiscalization under 54-FZ is a mandatory requirement. The fine for a missing receipt is up to 100% of the payment amount. In accordance with Federal Law No. 54-FZ, an electronic receipt must be sent to the buyer. We connect ATOL Online, Orange Data, Module.Kassa, Evotor, Shtrikh-M. Setup in Bitrix – the "Cash Registers" section in the sale module:

• VAT rate, item and method of payment – an error in any field can lead to a fine during inspection.
• Receipts for prepayment and partial payment (two receipts: at payment and at shipment).
• Refund receipts upon cancellation via \Bitrix\Sale\Cashbox\Cashbox::addChecks().
• Monitoring: if the receipt is not sent, an alert to the manager.

When selling shoes, clothing, or perfumes, it is mandatory to transfer marking codes in the receipt. Integration with "Chestny ZNAK", scanning DataMatrix during order assembly, automatic removal from circulation upon sale via \Bitrix\Catalog\Product\Marking.

Payment support: refunds, multicurrency, security

Refunds

Full and partial refund without calling the bank – via the aggregator API (refund / cancel). The refund receipt is generated automatically, the order status is updated, the amount is recalculated, and the customer is notified. Timeframes: e-wallets and SBP – 1–3 days, bank card – up to 30 business days (depends on the issuing bank).

Multicurrency

Price types in b_catalog_price for each currency, rates via the Central Bank API (\Bitrix\Currency\CurrencyManager::updateCBRFRates()) or manual input. Conversion at the catalog level – the customer sees prices in their currency. For accepting dollars/euros, we connect Stripe, PayPal. We take into account conversion fees when calculating margin.

Security

Card data is processed on the certified gateway side (PCI DSS) – the card number never passes through your server. Anti-fraud at the aggregator level. Logging all events in b_sale_order_change for audit. Anomaly monitoring: transaction spike, atypical geography – alert.

How we work and estimated timelines

1. Analysis – what payment methods are needed, markets, transaction volume, current aggregator.
2. Solution selection – sometimes two aggregators are better than one: YooKassa as the main, CloudPayments as backup – if one fails, traffic goes to the second.
3. Integration – we test each scenario: successful payment, 3DS refusal, gateway timeout, double callback, partial refund.
4. Fiscalization – online cash register, checking the correctness of receipts on test orders.
5. Monitoring – alerts for gateway failures, conversion dashboard at the payment stage.

What is included in the work

• Full setup of selected payment systems in 1C-Bitrix: modules, handlers, callbacks, testing.
• Integration documentation (gateway operation scheme, handler description, logic).
• Training your manager to work with payment modules and refunds.
• Technical support during launch and the first 2 weeks of operation.
• Monitoring – we set up alerts for errors and conversion drops.

All work is performed by certified 1C-Bitrix developers. We guarantee the operability of each scenario. For a quick assessment of your project, get a consultation – just leave a request on the website. Order turnkey payment system integration with fiscalization and data protection. Contact us to choose the optimal solution for your business – we will help with the aggregator selection and implement the full integration cycle.