.net encryption algorithm

public static string Encrypt(string source)
        {
            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            byte[] bytes = Encoding.UTF8.GetBytes(source);
            byte[] output = md5.ComputeHash(bytes);

            return BitConverter.ToString(output);
        }
最常见的MD5加密，但不带解密。

DES加解密。
  public class DES
    {
        private const string key = "av&6^3*E";
       
        public static string Encrypt(string source)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            byte[] bytes = Encoding.UTF8.GetBytes(source);

            des.Key = ASCIIEncoding.ASCII.GetBytes(key);
            des.IV = ASCIIEncoding.ASCII.GetBytes(key);

            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

            cs.Write(bytes, 0, bytes.Length);
            cs.FlushFinalBlock();

            StringBuilder sb = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                sb.AppendFormat("{0:X2}", b);
            }

            return sb.ToString();
        }

        public static string Decrypt(string source)
        {
            if (source == null || source.Length == 0)
            {
                return source;
            }

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] bytes = new byte[source.Length / 2];
            for (int x = 0; x < source.Length / 2; x++)
            {
                int i = (Convert.ToInt32(source.Substring(x * 2, 2), 16));
                bytes[x] = (byte)i;
            }

            des.Key = ASCIIEncoding.ASCII.GetBytes(key);
            des.IV = ASCIIEncoding.ASCII.GetBytes(key);

            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(bytes, 0, bytes.Length);
            cs.FlushFinalBlock();

            return Encoding.UTF8.GetString(ms.ToArray());
        }
    }