Omnipay\Redsys\Message\Security

Complexity

Total Complexity

7

Size/Duplication

Total Lines	86
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	1

Test Coverage

Coverage

100%

Importance

Changes	1
Bugs	0	Features	0

6 Methods

Rating	Name	Duplication	Size	Complexity
A	hasValidEncryptionMethod()	0	4	1
A	encodeMerchantParameters()	0	4	1
A	decodeMerchantParameters()	0	4	1
A	encryptMessage()	0	12	2
A	createSignature()	0	5	1
A	createReturnSignature()	0	4	1

<?php

namespace Omnipay\Redsys\Message;

use Omnipay\Common\Exception\RuntimeException;

/**
 * Security
 *
 * This class provides common encoding, decoding and signing functions.
 * While all of this code could be called statically, it is left as a
 * regular class in order to faciliate unit testing. If alternate
 * encryption methods are provided later, the VERSION const can be
 * switched to a constructor option (and validated against a whitelist).
 */
class Security
{
    /** @var string */
    const VERSION = 'HMAC_SHA256_V1';

    /**
     * Encode merchant parameters
     *
     * @param array $data  The parameters to encode
     *
     * @return string Encoded data
     */
    public function encodeMerchantParameters($data)
    {
        return base64_encode(json_encode($data));
    }

    /**
     * Decode merchant parameters
     *
     * @param string $data  The encoded string of parameters
     *
     * @return array Decoded data
     */
    public function decodeMerchantParameters($data)
    {
        return (array)json_decode(base64_decode(strtr($data, '-_', '+/')));
    }

    /**
     * Encrypt message with given key and default IV
     *
     * @param string $message  The message to encrypt
     * @param string $key      The key used to encrypt the message
     *
     * @return string Encrypted message
     *
     * @throws RuntimeException
     */
    protected function encryptMessage($message, $key)
    {
        $iv = implode(array_map('chr', array(0, 0, 0, 0, 0, 0, 0, 0)));

        if ($this->hasValidEncryptionMethod()) {
            $ciphertext = mcrypt_encrypt(MCRYPT_3DES, $key, $message, MCRYPT_MODE_CBC, $iv);
        } else {
            throw new RuntimeException('No valid encryption extension installed');
        }

        return $ciphertext;
    }

    /**
     * Check if the system has a valid encryption method available
     *
     * @todo add or switch to extension_loaded()?
     *
     * @return bool
     */
    public function hasValidEncryptionMethod()
    {
        return function_exists('mcrypt_encrypt');
    }

    /**
     * Create signature hash used to verify messages
     *
     * @todo Add if-check on algorithm to match against signature version as new param?
     *
     * @param string $message  The message to encrypt
     * @param string $salt     Unique salt used to generate the ciphertext
     * @param string $key      The key used to encrypt the message
     *
     * @return string Generated signature
     */
    public function createSignature($message, $salt, $key)
    {
        $ciphertext = $this->encryptMessage($salt, $key);
        return base64_encode(hash_hmac('sha256', $message, $ciphertext, true));
    }

    public function createReturnSignature($message, $salt, $key)
    {
        return strtr($this->createSignature($message, $salt, $key), '+/', '-_');
    }
}