diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4f38912
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.idea
+vendor
+composer.lock
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..52cc6dd
--- /dev/null
+++ b/README.md
@@ -0,0 +1,8 @@
+# Omnipay: ČSOB
+
+**ČSOB driver for the Omnipay PHP payment processing library**
+
+[Omnipay](https://github.com/thephpleague/omnipay) is a framework agnostic, multi-gateway payment
+processing library for PHP 5.3+. This package implements PayPal support for Omnipay.
+
+ČSOB Online Payment Gateway [documentation](https://github.com/csob/paymentgateway/wiki)
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..bca3c00
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,32 @@
+{
+  "name": "bileto/omnipay-csob",
+  "type": "library",
+  "description": "ČSOB gateway for Omnipay payment processing library",
+  "keywords": [
+    "gateway",
+    "merchant",
+    "omnipay",
+    "pay",
+    "payment",
+    "csob",
+    "purchase"
+  ],
+  "homepage": "https://github.com/bileto/omnipay-csob",
+  "license": "MIT",
+  "authors": [
+    {
+      "name": "Michal Sänger",
+      "email": "michal.sanger@bileto.cz"
+    }
+  ],
+  "autoload": {
+    "psr-4": { "Omnipay\\Csob\\" : "src/" }
+  },
+  "require": {
+    "omnipay/common": "^2.3"
+  },
+  "require-dev": {
+    "omnipay/tests": "^2.0",
+    "symfony/var-dumper": "^2.7"
+  }
+}
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..fc6bb9d
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit backupGlobals="false"
+         backupStaticAttributes="false"
+         bootstrap="tests/bootstrap.php"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false"
+         syntaxCheck="false">
+    <testsuites>
+        <testsuite name="Application Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <php>
+        <env name="APP_ENV" value="testing"/>
+        <env name="CACHE_DRIVER" value="array"/>
+        <env name="SESSION_DRIVER" value="array"/>
+        <env name="QUEUE_DRIVER" value="sync"/>
+    </php>
+</phpunit>
diff --git a/src/Gateway.php b/src/Gateway.php
new file mode 100644
index 0000000..2eacfe3
--- /dev/null
+++ b/src/Gateway.php
@@ -0,0 +1,118 @@
+<?php
+
+namespace Omnipay\Csob;
+
+use Omnipay\Common\AbstractGateway;
+use Omnipay\Common\Exception\InvalidResponseException;
+use Omnipay\Csob\Message\CompletePurchaseRequest;
+use Omnipay\Csob\Message\InitPaymentRequest;
+use Omnipay\Csob\Message\ProcessPaymentRequest;
+use Omnipay\Csob\Message\PaymentResponse;
+use Omnipay\Csob\Sign\DataSignator;
+use Omnipay\Csob\Sign\DataVerifier;
+
+class Gateway extends AbstractGateway
+{
+    /** @var DataSignator */
+    private $signator;
+
+    /** @var DataVerifier */
+    private $verifier;
+
+    /**
+     * Get gateway display name
+     *
+     * This can be used by carts to get the display name for each gateway.
+     */
+    public function getName()
+    {
+        return 'ČSOB';
+    }
+
+    /**
+     * @param DataSignator $signator
+     */
+    public function setSignator(DataSignator $signator)
+    {
+        $this->signator = $signator;
+    }
+
+    /**
+     * @param DataVerifier $verifier
+     */
+    public function setVerifier(DataVerifier $verifier)
+    {
+        $this->verifier = $verifier;
+    }
+
+    /**
+     * @param array $parameters
+     * @return InitPaymentRequest
+     * @throws \Exception
+     */
+    public function initPayment(array $parameters = array())
+    {
+        return $this->createRequest(InitPaymentRequest::class, $parameters);
+    }
+
+    /**
+     * @param array $parameters
+     * @return ProcessPaymentRequest
+     * @throws \Exception
+     */
+    public function processPayment(array $parameters = array())
+    {
+        return $this->createRequest(ProcessPaymentRequest::class, $parameters);
+    }
+
+    /**
+     * @param array $parameters
+     * @return InitPaymentRequest
+     * @throws \Exception
+     */
+    public function purchase(array $parameters = array())
+    {
+        $initRequest = $this->initPayment($parameters);
+        /** @var PaymentResponse $initResponse */
+        $initResponse = $initRequest->send();
+        if (!$initResponse->isSuccessful()) {
+            throw new InvalidResponseException($initResponse->getMessage(), $initResponse->getCode());
+        }
+        $processRequest = $this->processPayment([
+            'merchantId' => $initRequest->getMerchantId(),
+            'payId' => $initResponse->getTransactionReference(),
+            'dttm' => $initResponse->getDttm(),
+        ]);
+        return $processRequest;
+    }
+
+    /**
+     * @param array $parameters
+     * @return CompletePurchaseRequest
+     * @throws \Exception
+     */
+    public function completePurchase(array $parameters = array())
+    {
+        return $this->createRequest(CompletePurchaseRequest::class, $parameters);
+    }
+
+    protected function createRequest($class, array $parameters)
+    {
+        if (!($this->signator instanceof DataSignator)) {
+            throw new \Exception('Cannot create request, Signator is not set');
+        }
+        if (!($this->verifier instanceof DataVerifier)) {
+            throw new \Exception('Cannot create request, Verifier is not set');
+        }
+
+        /** @var \Omnipay\Csob\Message\AbstractRequest $request */
+        $request = parent::createRequest($class, $parameters);
+
+        $request->setSignator($this->signator);
+        $request->setVerifier($this->verifier);
+
+        return $request;
+    }
+
+
+}
\ No newline at end of file
diff --git a/src/GatewayFactory.php b/src/GatewayFactory.php
new file mode 100644
index 0000000..a0a9323
--- /dev/null
+++ b/src/GatewayFactory.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Omnipay\Csob;
+
+use Omnipay\Csob\Sign\DataSignator;
+use Omnipay\Csob\Sign\DataVerifier;
+use Omnipay\Csob\Sign\Preparer;
+use Omnipay\Csob\Sign\Signator;
+use Omnipay\Csob\Sign\Verifier;
+use Omnipay\Omnipay;
+
+class GatewayFactory
+{
+    /**
+     * @param string $publicKeyFilename
+     * @param string $privateKeyFilename
+     * @param string $privateKeyPassword
+     * @return Gateway
+     */
+    public static function createInstance($publicKeyFilename, $privateKeyFilename, $privateKeyPassword = null)
+    {
+        $preparer = new Preparer();
+        $signator = new Signator($privateKeyFilename, $privateKeyPassword);
+        $verifier = new Verifier($publicKeyFilename);
+        $dataSignator = new DataSignator($preparer, $signator);
+        $dataVerifier = new DataVerifier($preparer, $verifier);
+
+        /** @var \Omnipay\Csob\Gateway $gateway */
+        $gateway = Omnipay::create('Csob');
+        $gateway->setSignator($dataSignator);
+        $gateway->setVerifier($dataVerifier);
+        return $gateway;
+    }
+}
\ No newline at end of file
diff --git a/src/Message/AbstractRequest.php b/src/Message/AbstractRequest.php
new file mode 100644
index 0000000..eb7adac
--- /dev/null
+++ b/src/Message/AbstractRequest.php
@@ -0,0 +1,47 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+use Omnipay\Csob\Sign\DataSignator;
+use Omnipay\Csob\Sign\DataVerifier;
+
+abstract class AbstractRequest extends \Omnipay\Common\Message\AbstractRequest
+{
+    /** @var DataSignator */
+    private $signator;
+
+    /** @var DataVerifier */
+    private $verifier;
+
+    /**
+     * @param DataSignator $signator
+     */
+    public function setSignator(DataSignator $signator)
+    {
+        $this->signator = $signator;
+    }
+
+    /**
+     * @return DataSignator
+     */
+    public function getSignator()
+    {
+        return $this->signator;
+    }
+
+    /**
+     * @return DataVerifier
+     */
+    public function getVerifier()
+    {
+        return $this->verifier;
+    }
+
+    /**
+     * @param DataVerifier $verifier
+     */
+    public function setVerifier(DataVerifier $verifier)
+    {
+        $this->verifier = $verifier;
+    }
+}
\ No newline at end of file
diff --git a/src/Message/AbstractResponse.php b/src/Message/AbstractResponse.php
new file mode 100644
index 0000000..0859561
--- /dev/null
+++ b/src/Message/AbstractResponse.php
@@ -0,0 +1,77 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+use Omnipay\Csob\Sign\DataVerifier;
+
+class AbstractResponse extends \Omnipay\Common\Message\AbstractResponse
+{
+    /** @var DataVerifier */
+    private $verifier;
+
+    /** @var boolean */
+    private $isVerified;
+
+    /**
+     * @param DataVerifier $verifier
+     */
+    public function setVerifier(DataVerifier $verifier)
+    {
+        $this->verifier = $verifier;
+    }
+
+    public function isVerified()
+    {
+        if ($this->isVerified === null) {
+            $data = $this->getData();
+            $arrayKeys = ['payId', 'dttm', 'resultCode', 'resultMessage', 'paymentStatus', 'authCode', 'merchantData'];
+            $signature = $this->getSignature();
+            $this->isVerified = $this->verifier->verify($data, $arrayKeys, $signature);
+        }
+        return $this->isVerified;
+    }
+
+    /**
+     * Is the response successful?
+     *
+     * @return boolean
+     */
+    public function isSuccessful()
+    {
+        if (!$this->isVerified()) {
+            return false;
+        }
+        return $this->getCode() === 0 || $this->getCode() === "0";
+    }
+
+    public function getSignature()
+    {
+        if (isset($this->data['signature'])) {
+            return $this->data['signature'];
+        }
+    }
+
+    public function getDttm()
+    {
+        if (isset($this->data['dttm'])) {
+            return $this->data['dttm'];
+        }
+    }
+
+    public function getCode()
+    {
+        if (isset($this->data['resultCode'])) {
+            return $this->data['resultCode'];
+        }
+    }
+
+    public function getMessage()
+    {
+        if (!$this->isVerified()) {
+            return 'Verification error, the signature cannot be verified with given public key.';
+        }
+        if (isset($this->data['resultMessage'])) {
+            return $this->data['resultMessage'];
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Message/CompletePurchaseRequest.php b/src/Message/CompletePurchaseRequest.php
new file mode 100644
index 0000000..3fecc35
--- /dev/null
+++ b/src/Message/CompletePurchaseRequest.php
@@ -0,0 +1,70 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+class CompletePurchaseRequest extends AbstractRequest
+{
+    public function setAuthCode($value)
+    {
+        $this->setParameter('authCode', $value);
+    }
+
+    public function setSignature($value)
+    {
+        $this->setParameter('signature', $value);
+    }
+
+    public function setDttm($value)
+    {
+        $this->setParameter('dttm', $value);
+    }
+
+    public function setResultCode($value)
+    {
+        $this->setParameter('resultCode', $value);
+    }
+
+    public function setPayId($value)
+    {
+        $this->setParameter('payId', $value);
+    }
+
+    public function setResultMessage($value)
+    {
+        $this->setParameter('resultMessage', $value);
+    }
+
+    public function setPaymentStatus($value)
+    {
+        $this->setParameter('paymentStatus', $value);
+    }
+
+    public function setMerchantData($value)
+    {
+        $this->setParameter('merchantData', $value);
+    }
+
+    /**
+     * Get the raw data array for this message. The format of this varies from gateway to
+     * gateway, but will usually be either an associative array, or a SimpleXMLElement.
+     *
+     * @return mixed
+     */
+    public function getData()
+    {
+        return $this->getParameters();
+    }
+
+    /**
+     * Send the request with specified data
+     *
+     * @param  mixed $data The data to send
+     * @return PaymentResponse
+     */
+    public function sendData($data)
+    {
+        $response = new PaymentResponse($this, $data);
+        $response->setVerifier($this->getVerifier());
+        return $this->response = $response;
+    }
+}
\ No newline at end of file
diff --git a/src/Message/InitPaymentRequest.php b/src/Message/InitPaymentRequest.php
new file mode 100644
index 0000000..6638abc
--- /dev/null
+++ b/src/Message/InitPaymentRequest.php
@@ -0,0 +1,152 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+use Guzzle\Http\Message\RequestInterface;
+use Omnipay\Common\Message\ResponseInterface;
+
+class InitPaymentRequest extends AbstractRequest
+{
+
+    public function setMerchantId($value)
+    {
+        $this->setParameter('merchantId', $value);
+    }
+
+    public function getMerchantId()
+    {
+        return $this->getParameter('merchantId');
+    }
+
+    public function setOrderNo($value)
+    {
+        $this->setParameter('orderNo', $value);
+    }
+
+    public function setDttm($value)
+    {
+        $this->setParameter('dttm', $value);
+    }
+
+    public function setPayOperation($value)
+    {
+        $this->setParameter('payOperation', $value);
+    }
+
+    public function setPayMethod($value)
+    {
+        $this->setParameter('payMethod', $value);
+    }
+
+    public function setTotalAmount($value)
+    {
+        $this->setParameter('totalAmount', $value);
+    }
+
+    public function setCurrency($value)
+    {
+        $this->setParameter('currency', $value);
+    }
+
+    public function setClosePayment($value)
+    {
+        $this->setParameter('closePayment', $value);
+    }
+
+    public function setReturnUrl($value)
+    {
+        $this->setParameter('returnUrl', $value);
+    }
+
+    public function setReturnMethod($value)
+    {
+        $this->setParameter('returnMethod', $value);
+    }
+
+    public function setCart(array $value)
+    {
+        $this->setParameter('cart', $value);
+    }
+
+    public function setDescription($value)
+    {
+        $this->setParameter('description', $value);
+    }
+
+    public function setMerchantData($value)
+    {
+        $this->setParameter('merchantData', $value);
+    }
+
+    public function setCustomerId($value)
+    {
+        $this->setParameter('customerId', $value);
+    }
+
+    public function setLanguage($value)
+    {
+        $this->setParameter('language', $value);
+    }
+
+    /**
+     * Get the raw data array for this message. The format of this varies from gateway to
+     * gateway, but will usually be either an associative array, or a SimpleXMLElement.
+     *
+     * @return mixed
+     */
+    public function getData()
+    {
+        $data = [
+            "merchantId" => $this->getParameter('merchantId'),
+            "orderNo" => $this->getParameter('orderNo'),
+            "dttm" => $this->getParameter('dttm'),
+            "payOperation" => $this->getParameter('payOperation'),
+            "payMethod" => $this->getParameter('payMethod'),
+            "totalAmount" => $this->getParameter('totalAmount'),
+            "currency" => $this->getParameter('currency'),
+            "closePayment" => $this->getParameter('closePayment'),
+            "returnUrl" => $this->getParameter('returnUrl'),
+            "returnMethod" => $this->getParameter('returnMethod'),
+            "cart" => $this->getParameter('cart'),
+            "description" => $this->getParameter('description'),
+            "merchantData" => $this->getParameter('merchantData'),
+            "customerId" => $this->getParameter('customerId'),
+            "language" => $this->getParameter('language'),
+        ];
+        $data['signature'] = $this->signData($data);
+        return $data;
+    }
+
+    private function signData($data)
+    {
+        $arrayKeys = [
+            'merchantId', 'orderNo', 'dttm', 'payOperation', 'payMethod', 'totalAmount', 'currency', 'closePayment', 'returnUrl',
+            'returnMethod', 'cart', 'description', 'merchantData', 'customerId', 'language'
+        ];
+        return $this->getSignator()->sign($data, $arrayKeys);
+    }
+
+    /**
+     * Send the request with specified data
+     *
+     * @param  mixed $data The data to send
+     * @return ResponseInterface
+     */
+    public function sendData($data)
+    {
+        $httpRequest = $this->httpClient->createRequest(
+            RequestInterface::POST,
+            'https://iapi.iplatebnibrana.csob.cz/api/v1/payment/init',
+            ['Content-Type' => 'application/json'],
+            json_encode($data)
+        );
+
+        $httpResponse = $httpRequest->send();
+        $data = $httpResponse->json();
+        $response = new PaymentResponse($this, $data);
+        $response->setVerifier($this->getVerifier());
+
+        return $this->response = $response;
+    }
+
+}
\ No newline at end of file
diff --git a/src/Message/PaymentResponse.php b/src/Message/PaymentResponse.php
new file mode 100644
index 0000000..2fbaa0d
--- /dev/null
+++ b/src/Message/PaymentResponse.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+class PaymentResponse extends AbstractResponse
+{
+    public function getAuthCode()
+    {
+        if (isset($this->data['authCode'])) {
+            return $this->data['authCode'];
+        }
+    }
+
+    public function getTransactionReference()
+    {
+        if (isset($this->data['payId'])) {
+            return $this->data['payId'];
+        }
+    }
+
+
+    public function getPaymentStatus()
+    {
+        if (isset($this->data['paymentStatus'])) {
+            return $this->data['paymentStatus'];
+        }
+    }
+
+    public function getMerchantData()
+    {
+        if (isset($this->data['merchantData'])) {
+            return $this->data['merchantData'];
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Message/ProcessPaymentRequest.php b/src/Message/ProcessPaymentRequest.php
new file mode 100644
index 0000000..ac4acbc
--- /dev/null
+++ b/src/Message/ProcessPaymentRequest.php
@@ -0,0 +1,72 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+use Guzzle\Http\Message\RequestInterface;
+
+class ProcessPaymentRequest extends AbstractRequest
+{
+    public function setDttm($value)
+    {
+        return $this->setParameter('dttm', $value);
+    }
+
+    public function setPayId($value)
+    {
+        return $this->setParameter('payId', $value);
+    }
+
+    public function setMerchantId($value)
+    {
+        return $this->setParameter('merchantId', $value);
+    }
+
+    /**
+     * Get the raw data array for this message. The format of this varies from gateway to
+     * gateway, but will usually be either an associative array, or a SimpleXMLElement.
+     *
+     * @return mixed
+     */
+    public function getData()
+    {
+        return $this->getParameters();
+        $data = [
+            "merchantId" => $this->getParameter('merchantId'),
+            "payId" => $this->getParameter('payId'),
+            "dttm" => $this->getParameter('dttm'),
+        ];
+        return $data;
+    }
+
+    /**
+     * Send the request with specified data
+     *
+     * @param  mixed $data The data to send
+     * @return ProcessPaymentResponse
+     */
+    public function sendData($data)
+    {
+        $httpRequest = $this->httpClient->createRequest(
+            RequestInterface::GET,
+            $this->createUri()
+        );
+
+        $httpResponse = $httpRequest->send();
+        return $this->response = new ProcessPaymentResponse($this, $httpResponse->getEffectiveUrl());
+    }
+
+    private function createUri()
+    {
+        $uri = 'https://iapi.iplatebnibrana.csob.cz/api/v1/payment/process';
+
+        $signator = $this->getSignator();
+        $signature = $signator->sign($this->getParameters(), ['merchantId', 'payId', 'dttm']);
+
+        return $uri  . '/' .
+            urlencode($this->getParameter('merchantId')) . '/' .
+            urlencode($this->getParameter('payId')) . '/' .
+            urlencode($this->getParameter('dttm')) . '/' .
+            urlencode($signature);
+    }
+
+}
\ No newline at end of file
diff --git a/src/Message/ProcessPaymentResponse.php b/src/Message/ProcessPaymentResponse.php
new file mode 100644
index 0000000..4884cc2
--- /dev/null
+++ b/src/Message/ProcessPaymentResponse.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace Omnipay\Csob\Message;
+
+use Guzzle\Http\Message\RequestInterface as GuzzleRequestInterface;
+use Omnipay\Common\Message\AbstractResponse as OmnipayAbstractResponse;
+use Omnipay\Common\Message\RedirectResponseInterface;
+use Omnipay\Common\Message\RequestInterface;
+
+class ProcessPaymentResponse extends OmnipayAbstractResponse implements RedirectResponseInterface
+{
+    /** @var string */
+    private $redirectUrl;
+
+    function __construct(RequestInterface $request, $redirectUrl)
+    {
+        $this->redirectUrl = $redirectUrl;
+        parent::__construct($request, null);
+    }
+
+    /**
+     * Is the response successful?
+     *
+     * @return boolean
+     */
+    public function isSuccessful()
+    {
+        return false;
+    }
+
+    /**
+     * Gets the redirect target url.
+     */
+    public function getRedirectUrl()
+    {
+        return $this->redirectUrl;
+    }
+
+    /**
+     * Get the required redirect method (either GET or POST).
+     */
+    public function getRedirectMethod()
+    {
+        return GuzzleRequestInterface::GET;
+    }
+
+    /**
+     * Gets the redirect form data array, if the redirect method is POST.
+     */
+    public function getRedirectData()
+    {
+        return;
+    }
+
+    public function isRedirect()
+    {
+        return true;
+    }
+
+
+}
\ No newline at end of file
diff --git a/src/Sign/DataSignator.php b/src/Sign/DataSignator.php
new file mode 100644
index 0000000..f743776
--- /dev/null
+++ b/src/Sign/DataSignator.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Omnipay\Csob\Sign;
+
+class DataSignator
+{
+    /** @var Preparer */
+    private $preparer;
+
+    /** @var Signator */
+    private $signator;
+
+    function __construct(Preparer $preparer, Signator $signator)
+    {
+        $this->preparer = $preparer;
+        $this->signator = $signator;
+    }
+
+    /**
+     * @param array $data
+     * @param array $arrayKeys
+     * @return string Base64 encoded
+     */
+    public function sign(array $data, array $arrayKeys)
+    {
+        $strToSign = $this->preparer->getStringToSign($data, $arrayKeys);
+        return $this->signator->sign($strToSign);
+    }
+}
\ No newline at end of file
diff --git a/src/Sign/DataVerifier.php b/src/Sign/DataVerifier.php
new file mode 100644
index 0000000..36fcd03
--- /dev/null
+++ b/src/Sign/DataVerifier.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace Omnipay\Csob\Sign;
+
+class DataVerifier
+{
+    /** @var Preparer */
+    private $preparer;
+
+    /** @var Verifier */
+    private $verifier;
+
+    function __construct(Preparer $preparer, Verifier $verifier)
+    {
+        $this->preparer = $preparer;
+        $this->verifier = $verifier;
+    }
+
+    /**
+     * @param array $data
+     * @param array $arrayKeys
+     * @param string $signatureBase64
+     * @return bool
+     */
+    public function verify(array $data, array $arrayKeys, $signatureBase64)
+    {
+        $strToSign = $this->preparer->getStringToSign($data, $arrayKeys);
+        return $this->verifier->verify($strToSign, $signatureBase64);
+    }
+}
\ No newline at end of file
diff --git a/src/Sign/Preparer.php b/src/Sign/Preparer.php
new file mode 100644
index 0000000..1f1e07f
--- /dev/null
+++ b/src/Sign/Preparer.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Omnipay\Csob\Sign;
+
+class Preparer
+{
+    /**
+     * @param array $data
+     * @param array $arrayKeys
+     * @return string
+     */
+    public function getStringToSign(array $data, array $arrayKeys)
+    {
+        $str = '';
+        foreach ($arrayKeys as $key) {
+            if (!isset($data[$key]) || $data[$key] === null) {
+                continue;
+            }
+            $value = $data[$key];
+            if ($value === true) {
+                $str .= 'true';
+            } elseif ($value === false) {
+                $str .= 'false';
+            } elseif (is_array($value)) {
+                $str .= $this->getStringToSign($value, array_keys($value));
+            } else {
+                $str .= (string)$data[$key];
+            }
+            $str .= '|';
+        }
+        return rtrim($str, '|');
+    }
+}
\ No newline at end of file
diff --git a/src/Sign/Signator.php b/src/Sign/Signator.php
new file mode 100644
index 0000000..f407731
--- /dev/null
+++ b/src/Sign/Signator.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace Omnipay\Csob\Sign;
+
+class Signator
+{
+    /** @var string */
+    private $privateKeyFilename;
+
+    /** @var string */
+    private $privateKeyPassword;
+
+    function __construct($privateKeyFilename, $privateKeyPassword = null)
+    {
+        $this->privateKeyFilename = $privateKeyFilename;
+        $this->privateKeyPassword = $privateKeyPassword;
+    }
+
+    /**
+     * @param string $text
+     * @return string Base64 encoded
+     */
+    public function sign($text) {
+        $private = file_get_contents($this->privateKeyFilename);
+        $privateKeyId = openssl_get_privatekey($private, $this->privateKeyPassword);
+
+        openssl_sign($text, $signature, $privateKeyId);
+        $signature = base64_encode($signature);
+        openssl_free_key($privateKeyId);
+
+        return $signature;
+    }
+}
\ No newline at end of file
diff --git a/src/Sign/Verifier.php b/src/Sign/Verifier.php
new file mode 100644
index 0000000..2dce790
--- /dev/null
+++ b/src/Sign/Verifier.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace Omnipay\Csob\Sign;
+
+class Verifier
+{
+    /** @var string */
+    private $publicKeyFilename;
+
+    function __construct($publicKeyFilename)
+    {
+        $this->publicKeyFilename = $publicKeyFilename;
+    }
+
+    /**
+     * @param string $text
+     * @param string $signatureBase64
+     * @return bool
+     */
+    function verify($text, $signatureBase64) {
+        $public = file_get_contents($this->publicKeyFilename);
+        $publicKeyId = openssl_get_publickey($public);
+
+        $signature = base64_decode($signatureBase64);
+        $res = openssl_verify($text, $signature, $publicKeyId);
+        openssl_free_key($publicKeyId);
+
+        return $res === 1;
+    }
+}
\ No newline at end of file
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
new file mode 100644
index 0000000..d21c14d
--- /dev/null
+++ b/tests/bootstrap.php
@@ -0,0 +1,3 @@
+<?php
+
+require __DIR__ . '/../vendor/autoload.php';
diff --git a/tests/unit/Sign/DataSignatorTest.php b/tests/unit/Sign/DataSignatorTest.php
new file mode 100644
index 0000000..b0940a2
--- /dev/null
+++ b/tests/unit/Sign/DataSignatorTest.php
@@ -0,0 +1,56 @@
+<?php
+
+class DataSignatorTest extends PHPUnit_Framework_TestCase {
+
+    public function testSign()
+    {
+        $privateKey = __DIR__ . '/assets/rsa_A1029DTmM7.key';
+        $publicKey = __DIR__ . '/assets/rsa_A1029DTmM7.pub';
+        $preparer = new \Omnipay\Csob\Sign\Preparer();
+        $signator = new \Omnipay\Csob\Sign\Signator($privateKey);
+        $verifier = new \Omnipay\Csob\Sign\Verifier($publicKey);
+        $signator = new \Omnipay\Csob\Sign\DataSignator($preparer, $signator);
+
+        $data = [
+            "merchantId" => "A1029DTmM7",
+            "orderNo" => "1234560",
+            "dttm" => "20150624090323",
+            "payOperation" => "payment",
+            "payMethod" => "card",
+            "totalAmount" => 100,
+            "currency" => "CZK",
+            "closePayment" => "false",
+            "returnUrl" => "https://vasobchod.cz/gateway-return",
+            "returnMethod" => "POST",
+            "cart" => [
+                [
+                    "name" => "Shopping at ...",
+                    "quantity" => 1,
+                    "amount" => 100,
+                    "description" => "Lenovo ThinkPad Edge E540..."
+                ],
+                [
+                    "name" => "Shipping",
+                    "quantity" => 1,
+                    "amount" => 0,
+                    "description" => "PPL"
+                ]
+            ],
+            "description" => "Nákup na vasobchod.cz (Lenovo ThinkPad Edge E540, Doprava PPL)",
+            "merchantData" => null,
+            "customerId" => "1234",
+            "language" => "CZ",
+        ];
+        $arrayKeys = [
+            'merchantId', 'orderNo', 'dttm', 'payOperation', 'payMethod', 'totalAmount', 'currency', 'closePayment', 'returnUrl',
+            'returnMethod', 'cart', 'description', 'merchantData', 'customerId', 'language'
+        ];
+        $expectedSignature = "WaCyOg/6UikvZ3ut+B/6D7NaV1Vacj1eBzYEH19EC3Jwfe7fH2GyKliTK4dWZvTXNmnoAErRaR6+QSRmaQr12c2shyXG3XatfdYPRAjrneNnb3wgDwG/CgFAPc3xkw+9V2hVYiAP8QJtqX3dptvMWp+SjouGwP4jCUZQM9zebOkNdmsLn5QP8dj7qJ9n++AU0TG/WdImU0+RLMH4XRSp5xaebOVlzeLWXZKwPZB4EpVVlC/DEgF19t9dKMIKd+16Q9LVuRMPEvP/6zrx1EYbuGpV4Qbwdb5gSCyC3DkjB9gCRG0ZX8WftHsvVNbsFx9i4ujcg7SFK85KAsQuWTUXEw==";
+        $stringToSign = $preparer->getStringToSign($data, $arrayKeys);
+
+        $signature = $signator->sign($data, $arrayKeys);
+
+        $this->assertSame($expectedSignature, $signature);
+        $this->assertTrue($verifier->verify($stringToSign, $signature), 'Verification failed');
+    }
+}
diff --git a/tests/unit/Sign/DataVerifierTest.php b/tests/unit/Sign/DataVerifierTest.php
new file mode 100644
index 0000000..fe8a77e
--- /dev/null
+++ b/tests/unit/Sign/DataVerifierTest.php
@@ -0,0 +1,27 @@
+<?php
+
+class DataVerifierTest extends PHPUnit_Framework_TestCase
+{
+    public function testVerify()
+    {
+        $publicKey = __DIR__ . '/assets/mips_iplatebnibrana.csob.cz.pub';
+        $preparer = new \Omnipay\Csob\Sign\Preparer();
+        $verifier = new \Omnipay\Csob\Sign\Verifier($publicKey);
+        $dataVerifier = new \Omnipay\Csob\Sign\DataVerifier($preparer, $verifier);
+
+        $data = [
+            "authCode" => "518778",
+            "dttm" => "20150624173114",
+            "resultCode" => "0",
+            "payId" => "18b7c0eced91417",
+            "resultMessage" => "OK",
+            "paymentStatus" => "7"
+        ];
+        $arrayKeys =['payId', 'dttm', 'resultCode', 'resultMessage', 'paymentStatus', 'authCode'];
+        $signature = 'rnIFXMnHB3HW0xPgfhiScWZ6OMyp9iiaPzPf83aJ0MD5Fywf\/XPB6lVhOfqUfCC4qoD9YYZrWKPGyYAf7Fk6EK2qUewRdPSGLNcyX7xD5hWD65SJArXYhGwg9k3kkoxbMkAk\/tluTK6Hw2K65Xi2to1cIe\/lctXV2D92kisux6JKO9Ksw\/6eFOF3xFCWjIgxxy8\/oHQDo6EksNKef2SUH7fXPaG+A0SjuGeNs6kD3A8w2a40EZYZYcY00Ny9Xg2kV4uxRNHDFSph7LFkAo6G9p3j913\/A69ngX60hr13or+14cVgN2Lixk7RqjpdFHZ5bQjpShtTAT03WR+B2Z7pcg==';
+
+        $isVerified = $dataVerifier->verify($data, $arrayKeys, $signature);
+
+        $this->assertTrue($isVerified, 'Verification failed');
+    }
+}
diff --git a/tests/unit/Sign/PreparerTest.php b/tests/unit/Sign/PreparerTest.php
new file mode 100644
index 0000000..b58b96b
--- /dev/null
+++ b/tests/unit/Sign/PreparerTest.php
@@ -0,0 +1,98 @@
+<?php
+
+use Omnipay\Csob\Sign\Preparer;
+
+class PreparerTest extends PHPUnit_Framework_TestCase
+{
+    public function testGetDataToSign()
+    {
+        $preparer = new Preparer();
+        $data = [
+            "merchantId" => "A1029DTmM7",
+            "orderNo" => "1234560",
+            "dttm" => "20150624090323",
+            "payOperation" => "payment",
+            "payMethod" => "card",
+            "totalAmount" => 100,
+            "currency" => "CZK",
+            "closePayment" => "false",
+            "returnUrl" => "https://vasobchod.cz/gateway-return",
+            "returnMethod" => "POST",
+            "cart" => [
+                [
+                    "name" => "Shopping at ...",
+                    "quantity" => 1,
+                    "amount" => 100,
+                    "description" => "Lenovo ThinkPad Edge E540..."
+                ],
+                [
+                    "name" => "Shipping",
+                    "quantity" => 1,
+                    "amount" => 0,
+                    "description" => "PPL"
+                ]
+            ],
+            "description" => "Nákup na vasobchod.cz (Lenovo ThinkPad Edge E540, Doprava PPL)",
+            "merchantData" => null,
+            "customerId" => "1234",
+            "language" => "CZ",
+        ];
+        $keys = [
+            'merchantId', 'orderNo', 'dttm', 'payOperation', 'payMethod', 'totalAmount', 'currency', 'closePayment', 'returnUrl',
+            'returnMethod', 'cart', 'description', 'merchantData', 'customerId', 'language'
+        ];
+        $expectedStrToSign = "A1029DTmM7|1234560|20150624090323|payment|card|100|CZK|false|https://vasobchod.cz/gateway-return|POST|Shopping at ...|1|100|Lenovo ThinkPad Edge E540...|Shipping|1|0|PPL|Nákup na vasobchod.cz (Lenovo ThinkPad Edge E540, Doprava PPL)|1234|CZ";
+
+        $strToSign = $preparer->getStringToSign($data, $keys);
+
+        $this->assertSame($expectedStrToSign, $strToSign);
+    }
+
+    public function testGetDataToSignIgnoresNotRequestedKeys()
+    {
+        $preparer = new Preparer();
+        $data = [
+            "merchantId" => "A1029DTmM7",
+            "orderNo" => "1234567",
+            "totalAmount" => 100,
+            "currency" => "CZK",
+            "closePayment" => false,
+        ];
+        $keys = [
+            "merchantId",
+            "closePayment",
+        ];
+        $expectedStrToSign = "A1029DTmM7|false";
+
+        $strToSign = $preparer->getStringToSign($data, $keys);
+
+        $this->assertSame($expectedStrToSign, $strToSign);
+    }
+
+    public function testGetDataToSignIgnores()
+    {
+        $preparer = new Preparer();
+        $data = [
+            "merchantId" => "A1029DTmM7",
+            "cart" => [
+                [
+                    "name" => "Shopping at Foo",
+                    "quantity" => 1,
+                    "amount" => 100,
+                    "description" => "Lenovo ThinkPad Edge E540"
+                ],
+            ],
+            "currency" => "CZK",
+        ];
+        $keys = [
+            "merchantId",
+            "cart",
+            "currency",
+        ];
+        $expectedStrToSign = "A1029DTmM7|Shopping at Foo|1|100|Lenovo ThinkPad Edge E540|CZK";
+
+        $strToSign = $preparer->getStringToSign($data, $keys);
+
+        $this->assertSame($expectedStrToSign, $strToSign);
+    }
+}
diff --git a/tests/unit/Sign/SignatorTest.php b/tests/unit/Sign/SignatorTest.php
new file mode 100644
index 0000000..f60456d
--- /dev/null
+++ b/tests/unit/Sign/SignatorTest.php
@@ -0,0 +1,18 @@
+<?php
+
+class SignatorTest extends PHPUnit_Framework_TestCase
+{
+    public function testSign()
+    {
+        $privateKey = __DIR__ . '/assets/rsa_A1029DTmM7.key';
+        $publicKey = __DIR__ . '/assets/rsa_A1029DTmM7.pub';
+        $signator = new \Omnipay\Csob\Sign\Signator($privateKey);
+        $verifier = new \Omnipay\Csob\Sign\Verifier($publicKey);
+        $text = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec malesuada porta orci, eget vehicula tortor eleifend in.';
+
+        $signed = $signator->sign($text);
+
+        $this->assertNotSame($text, $signed);
+        $this->assertTrue($verifier->verify($text, $signed));
+    }
+}
diff --git a/tests/unit/Sign/VerifierTest.php b/tests/unit/Sign/VerifierTest.php
new file mode 100644
index 0000000..b43708c
--- /dev/null
+++ b/tests/unit/Sign/VerifierTest.php
@@ -0,0 +1,18 @@
+<?php
+
+class VerifierTest extends PHPUnit_Framework_TestCase
+{
+    public function testVerify()
+    {
+        $privateKey = __DIR__ . '/assets/rsa_A1029DTmM7.key';
+        $publicKey = __DIR__ . '/assets/rsa_A1029DTmM7.pub';
+        $signator = new \Omnipay\Csob\Sign\Signator($privateKey);
+        $verifier = new \Omnipay\Csob\Sign\Verifier($publicKey);
+        $text = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Maecenas metus arcu, accumsan in massa non';
+        $signed = $signator->sign($text);
+
+        $this->assertTrue($verifier->verify($text, $signed));
+        $this->assertFalse($verifier->verify('Other text', $signed));
+        $this->assertFalse($verifier->verify($text, 'Other signed text'));
+    }
+}
diff --git a/tests/unit/Sign/assets/mips_iplatebnibrana.csob.cz.pub b/tests/unit/Sign/assets/mips_iplatebnibrana.csob.cz.pub
new file mode 100644
index 0000000..56f14a8
--- /dev/null
+++ b/tests/unit/Sign/assets/mips_iplatebnibrana.csob.cz.pub
@@ -0,0 +1,9 @@
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAuo0GzBCQMl1wDJJrJHTQ
+ykGlh2Kon7QfQjKVTPv7fPIVE8PhHeJueWBfydqTQKVeIVMB9VAUYlaPjwFhAuJ6
+zqoaCG9m+q81L7CehsQThntxacOPwRd4SSyS5o+kPzTIFji0Z3c8s6pYJJoF+YfE
+atCWRW2frgrgbHbl+84AOvItt7NReYz1z4P7J+Uv4UbifFHVP7oIEh+5CJSj6puv
+jHh1QHrzE+dTaoKDhtOfSkTTelHqod/hUt4QIcHai6I8X/R5nEv3y40MWoi1FxbQ
+6IgtVMloneN0XaHR5U88eMeKJJyqR859I4xfun6Z6RyfyaIl5Ph3f2daeMeENPUR
+BQIDAQAB
+-----END PUBLIC KEY-----
diff --git a/tests/unit/Sign/assets/rsa_A1029DTmM7.key b/tests/unit/Sign/assets/rsa_A1029DTmM7.key
new file mode 100644
index 0000000..f6d9cd0
--- /dev/null
+++ b/tests/unit/Sign/assets/rsa_A1029DTmM7.key
@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIEpAIBAAKCAQEAnDl8QHxz98t94XOIL6djAPg58KX/+Bv4YzzusyJhnj3Hfnh+
+0YPPtDRQDaLaSVBpLl1W/LkoFSWwJvc2Wg7yR9fKQB3DV3C5fVVFbfpYaO6gJWCB
+ESU0IoAcnlnFS5UBfsTrD8c1F7Ic7MYyhcZefekS9htbDh5HrQxcEEpxkPRhKhgI
+EbbkabXWbTED5ZTznSgHLEogzZwhDhSCF1sQ6rrc65hBsR7WkCPmjVzFeBjRF0o+
+SQo0eql3CINsIZ2zLGhHHisVLAdWLrdoRkVeC6dSQDlF10B8tbSMEd+G3XGmsvzq
+Y9jdAiLFT3bERVzuD+x3J/jI1//vrxykiwS8DQIDAQABAoIBAG/2fwdUamSIMaJ3
+g33rr/fM7vF6dvXhTeYJkGVP2bhoPGZ2gyUzG5Ph/hGXymvKtmclPCeJp6FoTlPO
+zuRCW/+DNw82hX5Qao/ZohXM2rnxc1L2U+nuyOuE933BhrXBh73L8U9wjKt72mET
+NrhLUANbHFzHhD2dE++AsSZ3w+aHLsl12biRWhKA5xDNeWYwIXGVx1DhgBeB/wuZ
+oKNOw2H96gpDK4COdmXGekbch82EcHNaJYxI5tT0ZIHmcQFSiUJJFqtp5kYhd+n9
+2M7h82i6beXTbJWE7dug5GQMqSXUue7rGNc4BFOGzVXxCV3SKdp+Xdkrwb4kuo9u
+j2rXdb0CgYEA2WAEZCvNzYabv20sc8ri//Sf6NN36Y5Goc+19iLwYLIabM0bA/of
+dY5aGlp8x10i4voN+E7n88eyw86UYztlWp+uRMvvVFi6IVGO3Gu+qelKoH55lIEJ
+kRT98KFBFRQMhPuKnWMbUjbnNoPbkW7tbs8qchSg5kVZL7LrDAzpQl8CgYEAt/vY
+qRF4QGzo+SDFlRfecghuK3I1y3n9oMmhAI46+5A+607jPb/ASQpO1LBIy3chkPUA
+tNjKjhtC6Rt+Vlhp/CkwfuHLP2ktnZ+kF3j+FnNKYg9EpGXX7yayTR+WZgs5x82f
+v2C9N7XdyjCVdox8rYzxQxZapLd+V56zylADkRMCgYEAn/DbKk1kv03E+WO96nEk
+90mqA2jdeTbbV6H6c+GfVraVZOrBbvqx/RBB0dQ0rYgk7Dcq4kJEvwV3zkUIv77r
+Q3PsiOg476ndQji9UgfhISnrZA3LLW6IeHymoFA2D+lRkON4SXermaGWHHGGtAqX
+nwnFZG0zOltaVRNjiNlTJCcCgYEAhZNOaOkrEjNALeeSK73JnabrPZXM4q7t6jeZ
+McsRnaTLWZHLwAAgfacDNr3KDBaxAwot+h7PaL74JD/2yH+maxIIiIYsRxx4ptDJ
+lNUePHR1053cKzNZw+KnXwEI84tA5wQt8AcvOWxL20jMquYyetoyK4/mPWKPUtQB
+GmhfPosCgYB65eJtPl7ZWo/GkPnkIreGcZc1SyuppW60hEtOCDEdkgMEZz5U/YeF
+/DJd4bSwBKebHB2rFxA65vKP0gVj7A75vJxJeL1JZ57kMSMX7XF3YyS4EmeqxFGo
+bAjeKFnfK4LJ7OwduH8ZZkd4kLDHKUBWkyZWmrm9v0xoHf/9CUdA8A==
+-----END RSA PRIVATE KEY-----
\ No newline at end of file
diff --git a/tests/unit/Sign/assets/rsa_A1029DTmM7.pub b/tests/unit/Sign/assets/rsa_A1029DTmM7.pub
new file mode 100644
index 0000000..983778a
--- /dev/null
+++ b/tests/unit/Sign/assets/rsa_A1029DTmM7.pub
@@ -0,0 +1,9 @@
+-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAnDl8QHxz98t94XOIL6dj
+APg58KX/+Bv4YzzusyJhnj3Hfnh+0YPPtDRQDaLaSVBpLl1W/LkoFSWwJvc2Wg7y
+R9fKQB3DV3C5fVVFbfpYaO6gJWCBESU0IoAcnlnFS5UBfsTrD8c1F7Ic7MYyhcZe
+fekS9htbDh5HrQxcEEpxkPRhKhgIEbbkabXWbTED5ZTznSgHLEogzZwhDhSCF1sQ
+6rrc65hBsR7WkCPmjVzFeBjRF0o+SQo0eql3CINsIZ2zLGhHHisVLAdWLrdoRkVe
+C6dSQDlF10B8tbSMEd+G3XGmsvzqY9jdAiLFT3bERVzuD+x3J/jI1//vrxykiwS8
+DQIDAQAB
+-----END PUBLIC KEY-----
\ No newline at end of file