基于RSA的加密/解密示例C#代碼

/**//*

 * 基于RSA的加密/解密示例C#代碼

 * (采用字元串作為參數)RSA_Demo2

 * 

 * 夏春濤 Email:[email protected] 

 * Blog:http://bluesky521.cnblogs.com

 * 運作環境：.net2.0 framework

 * 備注：

 * 不對稱算法通常用于加密少量資料，如加密對稱密鑰和 IV。通常，

 * 執行不對稱加密的個人使用由另一方生成的公鑰。.NET Framework 

 * 為此目的而提供了 RSACryptoServiceProvider 類。

 */

using System;

using System.Security.Cryptography;

using System.Text;

class RSACSPSample

{

    static void Main()

        try

            string str_Plain_Text = "How are you?How are you?How are you?How are you?=-popopolA";

            Console.WriteLine("明文：" + str_Plain_Text);

            Console.WriteLine("長度：" + str_Plain_Text.Length.ToString());

            Console.WriteLine();

            RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

            string str_Public_Key;

            string str_Private_Key;

            string str_Cypher_Text = RSA_Encrypt(str_Plain_Text, out str_Public_Key,out str_Private_Key);

            Console.WriteLine("密文：" + str_Cypher_Text);

            Console.WriteLine("公鑰：" + str_Public_Key);

            Console.WriteLine("私鑰：" + str_Private_Key);

            string str_Plain_Text2 = RSA_Decrypt(str_Cypher_Text, str_Private_Key);

            Console.WriteLine("解密：" + str_Plain_Text2);

        }

        catch (ArgumentNullException)

            Console.WriteLine("Encryption failed.");

    }

    //RSA加密,随機生成公私鑰對并作為出參傳回

    static public string RSA_Encrypt(string str_Plain_Text, out string str_Public_Key, out string str_Private_Key)

        str_Public_Key = "";

        str_Private_Key = "";

        UnicodeEncoding ByteConverter = new UnicodeEncoding();

        byte[] DataToEncrypt = ByteConverter.GetBytes(str_Plain_Text);

            str_Public_Key = Convert.ToBase64String(RSA.ExportCspBlob(false));

            str_Private_Key = Convert.ToBase64String(RSA.ExportCspBlob(true));

            //OAEP padding is only available on Microsoft Windows XP or later.  

            byte[] bytes_Cypher_Text = RSA.Encrypt(DataToEncrypt, false);

            string str_Cypher_Text = Convert.ToBase64String(bytes_Cypher_Text);

            return str_Cypher_Text;

        catch (CryptographicException e)

            Console.WriteLine(e.Message);

            return null;

    //RSA解密

    static public string RSA_Decrypt(string str_Cypher_Text, string str_Private_Key)

        byte[] DataToDecrypt = Convert.FromBase64String(str_Cypher_Text);

            //RSA.ImportParameters(RSAKeyInfo);

            byte[] bytes_Public_Key = Convert.FromBase64String(str_Private_Key);

            RSA.ImportCspBlob(bytes_Public_Key);

            byte[] bytes_Plain_Text = RSA.Decrypt(DataToDecrypt, false);

            UnicodeEncoding ByteConverter = new UnicodeEncoding();

            string str_Plain_Text = ByteConverter.GetString(bytes_Plain_Text);

            return str_Plain_Text;

            Console.WriteLine(e.ToString());

}

備注:經測試明文長度超過58時會出現異常.