Accept payments across Zimbabwe with a single integration.

const crypto = require("crypto");

function encrypt(plaintextJson, encryptionKey) {
  const key = crypto.createHash("sha256").update(encryptionKey, "utf8").digest();  // 32 bytes
  const iv  = crypto.randomBytes(12);
  const c   = crypto.createCipheriv("aes-256-gcm", key, iv);
  const ct  = Buffer.concat([c.update(plaintextJson, "utf8"), c.final()]);
  const tag = c.getAuthTag();                                    // 16 bytes
  return Buffer.concat([iv, ct, tag]).toString("base64"); // iv ‖ ciphertext ‖ tag
}

function decrypt(b64, encryptionKey) {
  const key = crypto.createHash("sha256").update(encryptionKey, "utf8").digest();
  const buf = Buffer.from(b64, "base64");
  const iv  = buf.subarray(0, 12);
  const tag = buf.subarray(buf.length - 16);
  const ct  = buf.subarray(12, buf.length - 16);
  const d   = crypto.createDecipheriv("aes-256-gcm", key, iv);
  d.setAuthTag(tag);
  return Buffer.concat([d.update(ct), d.final()]).toString("utf8");
}

import javax.crypto.Cipher;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.Base64;

public final class XPayCrypto {
    private static final SecureRandom RNG = new SecureRandom();

    public static String encrypt(String json, String encryptionKey) throws Exception {
        byte[] key = MessageDigest.getInstance("SHA-256")
                .digest(encryptionKey.getBytes(StandardCharsets.UTF_8));
        byte[] iv = new byte[12];
        RNG.nextBytes(iv);
        Cipher c = Cipher.getInstance("AES/GCM/NoPadding");
        c.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "AES"), new GCMParameterSpec(128, iv));
        byte[] ct = c.doFinal(json.getBytes(StandardCharsets.UTF_8));   // ciphertext ‖ tag
        byte[] out = new byte[iv.length + ct.length];
        System.arraycopy(iv, 0, out, 0, iv.length);
        System.arraycopy(ct, 0, out, iv.length, ct.length);
        return Base64.getEncoder().encodeToString(out);              // iv ‖ ciphertext ‖ tag
    }

    public static String decrypt(String b64, String encryptionKey) throws Exception {
        byte[] key = MessageDigest.getInstance("SHA-256")
                .digest(encryptionKey.getBytes(StandardCharsets.UTF_8));
        byte[] all = Base64.getDecoder().decode(b64);
        byte[] iv  = Arrays.copyOfRange(all, 0, 12);
        byte[] ct  = Arrays.copyOfRange(all, 12, all.length);
        Cipher c = Cipher.getInstance("AES/GCM/NoPadding");
        c.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key, "AES"), new GCMParameterSpec(128, iv));
        return new String(c.doFinal(ct), StandardCharsets.UTF_8);
    }
}

using System;
using System.Security.Cryptography;
using System.Text;

public static class XPayCrypto
{
    public static string Encrypt(string json, string encryptionKey)
    {
        byte[] key = SHA256.HashData(Encoding.UTF8.GetBytes(encryptionKey)); // 32 bytes
        byte[] iv  = RandomNumberGenerator.GetBytes(12);
        byte[] pt  = Encoding.UTF8.GetBytes(json);
        byte[] ct  = new byte[pt.Length];
        byte[] tag = new byte[16];
        using var gcm = new AesGcm(key, 16);
        gcm.Encrypt(iv, pt, ct, tag);
        byte[] outBytes = new byte[iv.Length + ct.Length + tag.Length];
        Buffer.BlockCopy(iv,  0, outBytes, 0, iv.Length);
        Buffer.BlockCopy(ct,  0, outBytes, iv.Length, ct.Length);
        Buffer.BlockCopy(tag, 0, outBytes, iv.Length + ct.Length, tag.Length);
        return Convert.ToBase64String(outBytes);                       // iv ‖ ciphertext ‖ tag
    }

    public static string Decrypt(string b64, string encryptionKey)
    {
        byte[] key = SHA256.HashData(Encoding.UTF8.GetBytes(encryptionKey));
        byte[] all = Convert.FromBase64String(b64);
        byte[] iv  = all[..12];
        byte[] tag = all[^16..];
        byte[] ct  = all[12..^16];
        byte[] pt  = new byte[ct.Length];
        using var gcm = new AesGcm(key, 16);
        gcm.Decrypt(iv, ct, tag, pt);
        return Encoding.UTF8.GetString(pt);
    }
}

const crypto = require("crypto");

function encrypt(plaintextJson, encryptionKey) {
  const key = Buffer.from(encryptionKey, "utf8");   // 32 bytes → AES-256
  const iv  = key.subarray(0, 16);
  const c = crypto.createCipheriv("aes-256-cbc", key, iv);
  return Buffer.concat([c.update(plaintextJson, "utf8"), c.final()]).toString("base64");
}

function decrypt(b64, encryptionKey) {
  const key = Buffer.from(encryptionKey, "utf8");
  const iv  = key.subarray(0, 16);
  const d = crypto.createDecipheriv("aes-256-cbc", key, iv);
  return Buffer.concat([d.update(Buffer.from(b64, "base64")), d.final()]).toString("utf8");
}

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Base64;

public final class XPayCryptoCbc {

    public static String encrypt(String json, String encryptionKey) throws Exception {
        byte[] key = encryptionKey.getBytes(StandardCharsets.UTF_8);   // 32 bytes → AES-256
        IvParameterSpec iv = new IvParameterSpec(Arrays.copyOfRange(key, 0, 16));
        Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
        c.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "AES"), iv);
        return Base64.getEncoder().encodeToString(c.doFinal(json.getBytes(StandardCharsets.UTF_8)));
    }

    public static String decrypt(String b64, String encryptionKey) throws Exception {
        byte[] key = encryptionKey.getBytes(StandardCharsets.UTF_8);
        IvParameterSpec iv = new IvParameterSpec(Arrays.copyOfRange(key, 0, 16));
        Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
        c.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key, "AES"), iv);
        return new String(c.doFinal(Base64.getDecoder().decode(b64)), StandardCharsets.UTF_8);
    }
}

using System;
using System.Security.Cryptography;
using System.Text;

public static class XPayCryptoCbc
{
    public static string Encrypt(string json, string encryptionKey)
    {
        byte[] key = Encoding.UTF8.GetBytes(encryptionKey);   // 32 bytes → AES-256
        using var aes = Aes.Create();
        aes.Key = key; aes.IV = key[..16];
        aes.Mode = CipherMode.CBC; aes.Padding = PaddingMode.PKCS7;
        using var enc = aes.CreateEncryptor();
        byte[] pt = Encoding.UTF8.GetBytes(json);
        return Convert.ToBase64String(enc.TransformFinalBlock(pt, 0, pt.Length));
    }

    public static string Decrypt(string b64, string encryptionKey)
    {
        byte[] key = Encoding.UTF8.GetBytes(encryptionKey);
        using var aes = Aes.Create();
        aes.Key = key; aes.IV = key[..16];
        aes.Mode = CipherMode.CBC; aes.Padding = PaddingMode.PKCS7;
        using var dec = aes.CreateDecryptor();
        byte[] ct = Convert.FromBase64String(b64);
        return Encoding.UTF8.GetString(dec.TransformFinalBlock(ct, 0, ct.Length));
    }
}