using System;

using System.Security.Cryptography;

using System.Text;

​

namespace FECVisioAES {

​

    public class Program {

        public static String sha256_hash(String value)

        {

            StringBuilder Sb = new StringBuilder();

​

            using (SHA256 hash = SHA256Managed.Create()) {

                Encoding unicode = new UTF8Encoding();

                Byte[] result = hash.ComputeHash(unicode.GetBytes(value));

​

                foreach (Byte b in result)

                    Sb.Append(b.ToString("x2"));

            }

​

            return Sb.ToString();

        }

​

        public static void Main(string[] args)

        {

            Encoding unicode = new UTF8Encoding();

​

            string message = "{\"version\":\"iteration_1\"}";

            string password = "8ca2e1997cf3b1d1aea157f61e280806";

            string rawiv = "8ca2e1997cf3b1d1";

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            SHA256 mySHA256 = SHA256Managed.Create();

            byte[] key = unicode.GetBytes(sha256_hash(password).Substring(0, 32));

            byte[] iv = unicode.GetBytes(sha256_hash(rawiv).Substring(0, 16));

​

            string ciphertext = Encrypt(message, key, iv);

            Console.WriteLine("ciphertext : " + ciphertext);

​

            string plaintext = Decrypt(ciphertext, key, iv);

            Console.WriteLine("plaintext  : " + plaintext);

​

        }

​

        public static string Encrypt (string plainText, byte[] key, byte[] iv)

        {

            Encoding unicode = new UTF8Encoding();

​

            Byte[] toEncryptArray = unicode.GetBytes(plainText);

​

            System.Security.Cryptography.RijndaelManaged rm = new System.Security.Cryptography.RijndaelManaged {

                Key = key,

                Mode = System.Security.Cryptography.CipherMode.CFB,

                Padding = System.Security.Cryptography.PaddingMode.None,

                IV = iv,

                FeedbackSize = 8,

                BlockSize = 128

            };

​

            System.Security.Cryptography.ICryptoTransform cTransform = rm.CreateEncryptor();

            Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

​

            return Convert.ToBase64String(resultArray, 0, resultArray.Length);

        }

​

        public static string Decrypt (string cipherText, byte[] key, byte[] iv)

        {

            Encoding unicode = new UTF8Encoding();

​

            Byte[] toEncryptArray = Convert.FromBase64String(cipherText);

​

            System.Security.Cryptography.RijndaelManaged rm = new System.Security.Cryptography.RijndaelManaged {

                Key = key,

                Mode = System.Security.Cryptography.CipherMode.CFB,

                Padding = System.Security.Cryptography.PaddingMode.None,

                IV = iv,

                FeedbackSize = 8,

                BlockSize = 128

            };

​

            System.Security.Cryptography.ICryptoTransform cTransform = rm.CreateDecryptor();

            Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

​

            return unicode.GetString(resultArray);

        }

    }

}