How can I encrypt and decrypt using AES 128 without an IV?

kdh picture kdh · Oct 18, 2013 · Viewed 26.6k times · Source

I'm currently needing a way to encrypt a string and decrypt a byte array using AES-128 symmetrical encryption, in C#. I can't find a way how to do this, but maybe I've missed something.

Answer

Arif Ansari picture Arif Ansari · Oct 18, 2013

Import namespaces

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

     static void Main(string[] args)
        {
            string value = "@arifansari300<3>";

            string encryptedValue= EncryptDecrypt.Encrypt(value);

            string decryptedValue = EncryptDecrypt.Decrypt(encryptedValue);
        }

    public static string Encrypt(string clearText)
    {
        string EncryptionKey = "MAKV2SPBNI99212";
        byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
        using (Aes encryptor = Aes.Create())
        {
            Rfc2898DeriveBytes pdb = new 
                Rfc2898DeriveBytes(EncryptionKey, new byte[] 
                { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
            encryptor.Key = pdb.GetBytes(32);
            encryptor.IV = pdb.GetBytes(16);
            using (MemoryStream ms = new MemoryStream())
            {
                using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(clearBytes, 0, clearBytes.Length);
                    cs.Close();
                }
                clearText = Convert.ToBase64String(ms.ToArray());
            }
        }
        return clearText;
    }

    public static string Decrypt(string cipherText)
    {
        string EncryptionKey = "MAKV2SPBNI99212";
        byte[] cipherBytes = Convert.FromBase64String(cipherText);
        using (Aes encryptor = Aes.Create())
        {
            Rfc2898DeriveBytes pdb = new 
                Rfc2898DeriveBytes(EncryptionKey, new byte[] 
                { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
            encryptor.Key = pdb.GetBytes(32);
            encryptor.IV = pdb.GetBytes(16);
            using (MemoryStream ms = new MemoryStream())
            {
                using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(cipherBytes, 0, cipherBytes.Length);
                    cs.Close();
                }
                cipherText = Encoding.Unicode.GetString(ms.ToArray());
            }
        }
        return cipherText;
    }