C# Password protected encryption and decryption

using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using System.Security.Cryptography;

using System.Text;

using System.Threading.Tasks;

namespace EncryptStringSample

{

    public static class StringCipher

    {

        // This constant string is used as a "salt" value for the PasswordDeriveBytes function calls.

        // This size of the IV (in bytes) must = (keysize / 8).  Default keysize is 256, so the IV must be

        // 32 bytes long.  Using a 16 character string here gives us 32 bytes when converted to a byte array.

        private static readonly byte[] initVectorBytes = Encoding.ASCII.GetBytes("tu89geji340t89u2");

        // This constant is used to determine the keysize of the encryption algorithm.

        private const int keysize = 256;

        public static string Encrypt(string plainText, string passPhrase)

        {

            byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);

            using (PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null))

            {

                byte[] keyBytes = password.GetBytes(keysize / 8);

                using (RijndaelManaged symmetricKey = new RijndaelManaged())

                {

                    symmetricKey.Mode = CipherMode.CBC;

                    using (ICryptoTransform encryptor = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes))

                    {

                        using (MemoryStream memoryStream = new MemoryStream())

                        {

                            using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))

                            {

                                cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);

                                cryptoStream.FlushFinalBlock();

                                byte[] cipherTextBytes = memoryStream.ToArray();

                                return Convert.ToBase64String(cipherTextBytes);

                            }

                        }

                    }

                }

            }

        }

        public static string Decrypt(string cipherText, string passPhrase)

        {

            byte[] cipherTextBytes = Convert.FromBase64String(cipherText);

            using(PasswordDeriveBytes password = new PasswordDeriveBytes(passPhrase, null))

            {

                byte[] keyBytes = password.GetBytes(keysize / 8);

                using(RijndaelManaged symmetricKey = new RijndaelManaged())

                {

                    symmetricKey.Mode = CipherMode.CBC;

                    using(ICryptoTransform decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes))

                    {

                        using(MemoryStream memoryStream = new MemoryStream(cipherTextBytes))

                        {

                            using(CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))

                            {

                                byte[] plainTextBytes = new byte[cipherTextBytes.Length];

                                int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);

                                return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);

                            }

                        }

                    }

                }

            }

        }

    }

}