C#加密解密大全

       }
         return encryptPassword ;
    }

            for ( int i=0; i < str.Length; i++)
            {
                dtext = dtext + (char) (str[i] - 10 + 1*2);
            }
            return dtext;
        }

        public string Encode(string data)
        {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            int i = cryptoProvider.KeySize;
            MemoryStream ms = new MemoryStream();
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);

            StreamWriter sw = new StreamWriter(cst);
            sw.Write(data);
            sw.Flush();
            cst.FlushFinalBlock();
            sw.Flush();
            return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);

        }

        public string Decode(string data)
         {
            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);

            byte[] byEnc;
            try
            {
                byEnc = Convert.FromBase64String(data);
            }
            catch
            {
                return null;
            }

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            MemoryStream ms = new MemoryStream(byEnc);
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);
            StreamReader sr = new StreamReader(cst);
            return sr.ReadToEnd();
        }

        }
        return sb.ToString();
    }

        return t2;
    } 

         //加密文件
    private static void EncryptData(String inName, String outName, byte[] desKey, byte[] desIV)
    {
        //Create the file streams to handle the input and output files.
        FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read);
        FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, FileAccess.Write);
        fout.SetLength(0);

        //Create variables to help with read and write.
        byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
        long rdlen = 0;              //This is the total number of bytes written.
        long totlen = fin.Length;    //This is the total length of the input file.
        int len;                     //This is the number of bytes to be written at a time.

        DES des = new DESCryptoServiceProvider();
        CryptoStream encStream = new CryptoStream(fout, des.CreateEncryptor(desKey, desIV), CryptoStreamMode.Write);

        //Read from the input file, then encrypt and write to the output file.
        while (rdlen < totlen)
        {
            len = fin.Read(bin, 0, 100);
            encStream.Write(bin, 0, len);
            rdlen = rdlen + len;
        }

        encStream.Close();
        fout.Close();
        fin.Close();
    }

    //解密文件
    private static void DecryptData(String inName, String outName, byte[] desKey, byte[] desIV)
    {
        //Create the file streams to handle the input and output files.
        FileStream fin = new FileStream(inName, FileMode.Open, FileAccess.Read);
        FileStream fout = new FileStream(outName, FileMode.OpenOrCreate, FileAccess.Write);
        fout.SetLength(0);

        //Create variables to help with read and write.
        byte[] bin = new byte[100]; //This is intermediate storage for the encryption.
        long rdlen = 0;              //This is the total number of bytes written.
        long totlen = fin.Length;    //This is the total length of the input file.
        int len;                     //This is the number of bytes to be written at a time.

        DES des = new DESCryptoServiceProvider();
        CryptoStream encStream = new CryptoStream(fout, des.CreateDecryptor(desKey, desIV), CryptoStreamMode.Write);

        //Read from the input file, then encrypt and write to the output file.
        while (rdlen < totlen)
        {
            len = fin.Read(bin, 0, 100);
            encStream.Write(bin, 0, len);
            rdlen = rdlen + len;
        }

        encStream.Close();
        fout.Close();
        fin.Close();
    }

        /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
        public static string DecryptDES(string decryptString, string decryptKey)
         {
            try
             {
                byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(mStream.ToArray());
            }
            catch
             {
                return decryptString;
            }
        } 


    }
}