Encryption & Decryption

Encryption and Decryption function for decrypting merchant transaction

Javascript

Encryption

  let key = crypto.createHash('sha256').update(String(merchant_secret_key)).digest('base64').substr(0, 32);
  let IV = crypto.createHash('sha256').update(String(merchant_public_key)).digest('base64').substr(0, 16);
  const cipher = crypto.createCipheriv('aes256', key, IV);
  let encrypted = cipher.update(JSON.stringify(body), 'utf8', 'base64');
  return encrypted += cipher.final('base64');

Decryption

 let key = crypto.createHash('sha256').update(String(merchant_secret_key)).digest('base64').substr(0, 32);
 let IV = crypto.createHash('sha256').update(String(merchant_public_key)).digest('base64').substr(0, 16);
 const decipher = crypto.createDecipheriv('aes256', key, IV);
  let decrypted = decipher.update(body, 'base64', 'utf8');
  decrypted += decipher.final('utf8');
  return JSON.parse(decrypted);

Python

from Crypto.Cipher import AES
import base64
import hashlib


def _pad(s): return s + (AES.block_size - len(s) % AES.block_size) * chr(AES.block_size - len(s) % AES.block_size) 
def _cipher():
    key = hashlib.md5(merchant_secret_key).hexdigest() # 32 character hexadecimal
    iv = hashlib.md5(merchant_public_key).digest() # 16 byte binary
    return AES.new(key=key, mode=AES.MODE_CBC, IV=iv)

def encrypt_token(data):
    return _cipher().encrypt(_pad(data))
    
def decrypt_token(data):
    return _cipher().decrypt(data)

if __name__ == '__main__':
    print('Python encrypt: ' + base64.b64encode(encrypt_token('dmyz.org')))
    print('Python decrypt: ' + decrypt_token(base64.b64decode('FSfhJ/gk3iEJOPVLyFVc2Q==')))

PHP

<?php

class AES
{
     
    function encryptToken($data, $merchant_secret_key, $merchant_public_key)
    {
        $key = substr(hash('sha256', $merchant_secret_key, true), 0, 32);
         $iv = substr(hash('sha256', $merchant_public_key, true), 0, 16);
        // use openssl:
        return openssl_encrypt($data, 'aes256', $key, OPENSSL_RAW_DATA, $iv);
    }

    function decryptToken($data, $merchant_secret_key, $merchant_public_key)
    {
        $key = substr(hash('sha256', $merchant_secret_key, true), 0, 32);
     $iv = substr(hash('sha256', $merchant_public_key, true), 0, 16);
        // use openssl:
        return openssl_decrypt(base64_decode($data), 'aes256', $key, OPENSSL_RAW_DATA, $iv);
    
    }
}

$aes = new AES();
$arr = array(
  'transaction_reference'=>'49test_1',
  'virtual_account_number'=>'4899284992',
  'principal_amount'=> '2350.00',
  'settled_amount'=> '2338.25',
  'fee_charged'=> '11.75',
  'transaction_date'=> '2022-02-19T00:00:00.000Z',
  'customer_identifier'=> '10A2',
  'transaction_indicator'=> 'C',
  'remarks'=> 'Payment from 10A2 to 4899284992',
  'currency'=> 'NGN',
  'channel'=> 'virtual-account'
);

echo ('PHP encrypt: '.base64_encode($aes->encryptToken(json_encode($arr), 'staging_sk_sample-secret-key-1', 'staging_pk_sample-public-key-1')))."\n";
echo ('PHP decrypt: '.$aes->decryptToken('Ajc/9TOSwbz1lTReb7BTo4XjL7bzJ0GWIxuncvSXfK83ZsYFt4bOt5+QQRz0jFFNSf6+7Axuqp91rR7aD/YwYczQQgUM+7QrK7nTw1KJbwTvPSSk3/IEektOlUx7DK7uXHlBBN9eVmn8tfDLKrsgj7zhymQhCfCoUTcDou3UyYWbKitwGH0o2X3hZo7cVqqq6Khnb12EwlK2kVhZvAjnu5g+T7erI1+RSb3jjab0MguWO6I3oXs9OGsiQKmCqZn564/q3ojArjk5OR8r3jBFgH4d96FoXS536rS8Toh5KPIVSGUjXLthcsWdgQ2VNzqBJ2iktzftFNgQRMdxQFCpaE0JwTKVkAyX0n3JDXt7DC+cTY+cHvAHRtl0zYhhrqT0WX4x95h+/WCdT27FEIJJJqJPBPHS1VAXwPS/v5sPGqdkqgFngTrYPaExk3YWoTxhonzT2tkagsGCaDuk8eptSA==', 'staging_sk_sample-secret-key-1', 'staging_pk_sample-public-key-1'))."\n";

?>

C#

using System;  
using System.IO;  
using System.Security.Cryptography;  
class ManagedAesSample {  
    public static void Main() {  
        Console.WriteLine("Enter text that needs to be encrypted..");  
        string data = Console.ReadLine();  
        EncryptAesManaged(data);  
        Console.ReadLine();  
    }  
    static void EncryptAesManaged(string raw) {  
        try {  
            // Create Aes that generates a new key and initialization vector (IV).    
            // Same key must be used in encryption and decryption    
            using(AesManaged aes = new AesManaged()) {  
                // Encrypt string    
                byte[] encrypted = Encrypt(raw, aes.Key, aes.IV);  
                // Print encrypted string    
                Console.WriteLine($ "Encrypted data: {System.Text.Encoding.UTF8.GetString(encrypted)}");  
                // Decrypt the bytes to a string.    
                string decrypted = Decrypt(encrypted, aes.Key, aes.IV);  
                // Print decrypted string. It should be same as raw data    
                Console.WriteLine($ "Decrypted data: {decrypted}");  
            }  
        } catch (Exception exp) {  
            Console.WriteLine(exp.Message);  
        }  
        Console.ReadKey();  
    }  
    static byte[] Encrypt(string plainText, byte[] Key, byte[] IV) {  
        byte[] encrypted;  
        // Create a new AesManaged.    
        using(AesManaged aes = new AesManaged()) {  
            // Create encryptor    
            ICryptoTransform encryptor = aes.CreateEncryptor(Key, IV);  
            // Create MemoryStream    
            using(MemoryStream ms = new MemoryStream()) {  
                // Create crypto stream using the CryptoStream class. This class is the key to encryption    
                // and encrypts and decrypts data from any given stream. In this case, we will pass a memory stream    
                // to encrypt    
                using(CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write)) {  
                    // Create StreamWriter and write data to a stream    
                    using(StreamWriter sw = new StreamWriter(cs))  
                    sw.Write(plainText);  
                    encrypted = ms.ToArray();  
                }  
            }  
        }  
        // Return encrypted data    
        return encrypted;  
    }  
    static string Decrypt(byte[] cipherText, byte[] Key, byte[] IV) {  
        string plaintext = null;  
        // Create AesManaged    
        using(AesManaged aes = new AesManaged()) {  
            // Create a decryptor    
            ICryptoTransform decryptor = aes.CreateDecryptor(Key, IV);  
            // Create the streams used for decryption.    
            using(MemoryStream ms = new MemoryStream(cipherText)) {  
                // Create crypto stream    
                using(CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read)) {  
                    // Read crypto stream    
                    using(StreamReader reader = new StreamReader(cs))  
                    plaintext = reader.ReadToEnd();  
                }  
            }  
        }  
        return plaintext;  
    }  
}