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：

<?xml version="1.0"?>
<configuration>
<appSettings>
<add key="IV" value="SuFjcEmp/TE="/>
<add key="Key" value="KIPSToILGp6fl+3gXJvMsN4IajizYBBT"/>
</appSettings>
</configuration>

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

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;

/// <summary>
///构造函数
/// </summary>
public CryptoHelper()
{
IV = ConfigurationManager.AppSettings["IV"];
Key = ConfigurationManager.AppSettings["Key"];
}
}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

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：

/// <summary>
/// 获取加密服务类
/// </summary>
/// <returns></returns>
private TripleDESCryptoServiceProvider GetCryptoProvider()
{
TripleDESCryptoServiceProvider provider = new TripleDESCryptoServiceProvider();

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

return provider;
}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

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：

/// <summary>
/// 获取加密后的字符串
/// </summary>
/// <param name="inputValue">输入值.</param>
/// <returns></returns>
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);
}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

解密方法也类似：

/// <summary>
/// 获取解密后的值
/// </summary>
/// <param name="inputValue">经过加密后的字符串.</param>
/// <returns></returns>
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());
}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

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"];
}

/// <summary>
/// 获取加密后的字符串
/// </summary>
/// <param name="inputValue">输入值.</param>
/// <returns></returns>
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);
}

/// <summary>
/// 获取加密服务类
/// </summary>
/// <returns></returns>
private TripleDESCryptoServiceProvider GetCryptoProvider()
{
TripleDESCryptoServiceProvider provider = new TripleDESCryptoServiceProvider();

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

return provider;

}

/// <summary>
/// 获取解密后的值
/// </summary>
/// <param name="inputValue">经过加密后的字符串.</param>
/// <returns></returns>
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());
}
}
}

使用例子：





原文地址：http://blogs.msdn.com/b/nikhiln/archive/2008/05/18/net-2-0-symmetric-encryption-code-sample.aspx