Asp.net,C# 加密解密字符串

首先在web.config | app.config 文件下增加如下代码： 
 
   
     
       
       
     
   



IV:加密算法的初始向量。 

Key：加密算法的密钥。 



接着新建类CryptoHelper,作为加密帮助类。 

首先要从配置文件中得到IV 和Key。所以基本代码如下： 
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; 

            ///

 
            ///构造函数 
            ///

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





注意添加System.Configuration.dll程序集引用。 



在获得了IV 和Key 之后，需要获取提供加密服务的Service 类。 

在这里，使用的是System.Security.Cryptography; 命名空间下的TripleDESCryptoServiceProvider类。 

获取TripleDESCryptoServiceProvider 的方法如下： 
///

 
        /// 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; 
        } 



TripleDESCryptoServiceProvider 两个有用的方法 

CreateEncryptor:创建对称加密器对象ICryptoTransform. 

CreateDecryptor:创建对称解密器对象ICryptoTransform 

加密器对象和解密器对象可以被CryptoStream对象使用。来对流进行加密和解密。 

cryptoStream 的构造函数如下： 
public CryptoStream(Stream stream, ICryptoTransform transform, CryptoStreamMode mode); 

使用transform 对象对stream 进行转换。 



完整的加密字符串代码如下： 
///

 
        /// 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); 
        } 





解密方法也类似： 
///

 
        /// 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()); 
        } 





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()); 
        } 
    } 
}