Asp.net,C# encryption and decryption string

First add the following code under the web.config | app.config file:




                                                                 the initial vector.

Key: The key of the encryption algorithm.



Then create a new class CryptoHelper as an encryption helper class.

First you need to get the IV and Key from the configuration file. So the basic code is as follows:
public class CryptoHelper
                                                                                                                                                         public class Cryp                                                     //private readonly string IV =       ILGp6fl+3gXJvMsN4IajizYBBT";
                 private readonly string Key = string.Empty;                                                          public CryptoHelper()
                                                                                 "];
                  Key = ConfigurationManager.AppSettings["Key"];



After obtaining the IV and Key, you need to obtain the Service class that provides encryption services.

Here, the TripleDESCryptoServiceProvider class under the System.Security.Cryptography; namespace is used. Le The method of obtaining TripleDeScryptoserviceProvider is as follows:
//// & lt; Summary & gt;
/// Get the encryption service category
// & lt;/summary & gt;
/// & lt; return; /Return & GT; ()
                                    TripleDESCryptoServiceProvider        provider = new TripleDESCryptoServiceProvider();                                                                      String(Key);

                                                                                     Two useful methods

CreateEncryptor: Create a symmetric encryptor object ICryptoTransform.

CreateDecryptor: Create a symmetric decryptor object ICryptoTransform

Encryptor objects and decryptor objects can be used by CryptoStream objects. to encrypt and decrypt streams.

The constructor of cryptoStream is as follows:
public CryptoStream(Stream stream, ICryptoTransform transform, CryptoStreamMode mode);

Use the transform object to convert the stream. The complete encrypted string code is as follows:
/// & lt; Summary & gt;
/// Get the encrypted string
//// & lt;/summary & gt;
/// & lt; param name = "inputvalue ">Enter value.
                                                                                                     Public String Getencryptedvalue (String InputValue) {
TriptedesCryptoserViceProvider = This.getCryptoprovider (); The tightly stream
Memorystream mstream = New Memorystream ();

// Create an encrypted conversion flow
CryptoStream cStream = new CryptoStream(mStream,
                                                                                                                        use using UTF8 encoding to get the bytes of the input string. T byte [] toencrypt = New Utf8enCoding (). Getbytes (inputValue);

// Write the byte into the conversion flow.
                   cStream.Write(toEncrypt, 0, toEncrypt.Length);          cStream.FlushFinalBlock();                                                                                                                                                                                                     cStream. . ​​​​//Encode the encrypted bytes into 64-bit format.
                                                                                                                Return                                                                                { TripleDESCryptoServiceProvider provider = this.GetCryptoProvider();

byte[] inputEquivalent = Convert.FromBase64String(inputValue);

                                                                                                                                                                                           

                                                                                                                                                                                                                                        // Create conversion flow.
          CryptoStream csDecrypt = new CryptoStream(msDecrypt,
                                                                                                                                      CryptoStreamMode.Write); csDecrypt.FlushFinalBlock();
                 csDecrypt.Close( );

            //获取字符串。 
            return new UTF8Encoding().GetString(msDecrypt.ToArray()); 
        } 





完整的CryptoHelper代码如下： 
using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Security.Cryptography; 
using System.IO; 
using System.Configuration; 

namespace WindowsFormsApplication1 
{ 
    public class CryptoHelper 
    { 
        //private readonly string IV = "SuFjcEmp/TE="; 
        private readonly string IV = string.Empty; 
        //private readonly string Key = "KIPSToILGp6fl+3gXJvMsN4IajizYBBT"; 
        private readonly string Key = string.Empty; 

        public CryptoHelper() 
        { 
            IV = ConfigurationManager.AppSettings["IV"]; 
            Key = ConfigurationManager.AppSettings["Key"]; 
        } 

        ///

 
        /// 获取加密后的字符串 
        ///

 
        /// 输入值. 
        ///  
        public string GetEncryptedValue(string inputValue) 
        { 
            TripleDESCryptoServiceProvider provider = this.GetCryptoProvider(); 

            // 创建内存流来保存加密后的流 
            MemoryStream mStream = new MemoryStream(); 

            // 创建加密转换流 
            CryptoStream cStream = new CryptoStream(mStream, 

            provider.CreateEncryptor(), CryptoStreamMode.Write); 
            // 使用UTF8编码获取输入字符串的字节。 
            byte[] toEncrypt = new UTF8Encoding().GetBytes(inputValue); 

            // 将字节写到转换流里面去。 
            cStream.Write(toEncrypt, 0, toEncrypt.Length); 
            cStream.FlushFinalBlock(); 

            // 在调用转换流的FlushFinalBlock方法后，内部就会进行转换了,此时mStream就是加密后的流了。 
            byte[] ret = mStream.ToArray(); 

            // Close the streams. 
            cStream.Close(); 
            mStream.Close(); 

            //将加密后的字节进行64编码。 
            return Convert.ToBase64String(ret); 
        } 

        ///

 
        /// 获取加密服务类 
        ///

 
        ///  
        private TripleDESCryptoServiceProvider GetCryptoProvider() 
        { 
            TripleDESCryptoServiceProvider provider = new TripleDESCryptoServiceProvider(); 

            provider.IV = Convert.FromBase64String(IV); 
            provider.Key = Convert.FromBase64String(Key); 

            return provider; 

        } 

        ///

 
        /// 获取解密后的值 
        ///

 
        /// 经过加密后的字符串. 
        ///  
        public string GetDecryptedValue(string inputValue) 
        { 
            TripleDESCryptoServiceProvider provider = this.GetCryptoProvider(); 
            byte[] inputEquivalent = Convert.FromBase64String(inputValue); 

            // 创建内存流保存解密后的数据 
            MemoryStream msDecrypt = new MemoryStream(); 

            // 创建转换流。 
            CryptoStream csDecrypt = new CryptoStream(msDecrypt, 
            provider.CreateDecryptor(), 
            CryptoStreamMode.Write); 

            csDecrypt.Write(inputEquivalent, 0, inputEquivalent.Length); 
            csDecrypt.FlushFinalBlock(); 

            csDecrypt.Close(); 

            //获取字符串。 
            return new UTF8Encoding().GetString(msDecrypt.ToArray()); 
        } 
    } 
}