c# rsa加密解密详解-C#/.NET开发

这篇文章主要介绍了c# rsa加密解密的的相关资料，文中代码非常细致，帮助大家更好的理解和学习，感兴趣的朋友可以了解下

前言

RSA加密算法是一种非对称加密算法，简单来说，就是加密时使用一个钥匙，解密时使用另一个钥匙。

因为加密的钥匙是公开的，所又称公钥，解密的钥匙是不公开的，所以称为私钥。

密钥

关于RSA加密有很多文章，但几乎都只介绍了RSACryptoServiceProvider类的使用方法，如果只是走走看看，是没问题的，但真的想使用时，就会发现，你没有密钥字符串。。。

下面我们从获取密钥字符串开始逐步学习加密。

密钥字符串

每个安装过VisualStudio的电脑都可以找到一个文件—makecert.exe。

我电脑的makecert.exe地址：C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Bin\makecert.exe

makecert.exe是用来生成证书的程序，我们可以借用该程序来获取密钥字符串。


public static bool CreateCertWithPrivateKey(string subjectName, string makecertPath)
{
  subjectName = "CN=" + subjectName;
  string param = " -pe -ss my -n \"" + subjectName + "\" ";
  try
  {
    Process p = Process.Start(makecertPath, param);
    p.WaitForExit();
    p.Close();
  }
  catch (Exception e)
  {
    return false;
  }
  return true;
}

调用证书生成函数，代码如下：


string keyName = "Kiba518.Licence";//证书的KEY
var ret = DataCertificate.CreateCertWithPrivateKey(keyName, @"C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\Bin\makecert.exe");

刚刚生成的证书还存储在WINDOWS的证书存储区，现在我们通过证书的Key在证书存储区查找到证书，并将其到出（导出时需要指定密码），导出函数代码如下：


public static bool ExportToPfxFile(string subjectName, string pfxFileName,
  string password, bool isDelFromStore)
{
  subjectName = "CN=" + subjectName;
  X509Store store = new X509Store(StoreName.My, StoreLocation.CurrentUser);
  store.Open(OpenFlags.ReadWrite);
  X509Certificate2Collection storecollection = (X509Certificate2Collection)store.Certificates;
  foreach (X509Certificate2 x509 in storecollection)
  {
    if (x509.Subject == subjectName)
    {
      byte[] pfxByte = x509.Export(X509ContentType.Pfx, password);
      using (FileStream fileStream = new FileStream(pfxFileName, FileMode.Create))
      {
        // Write the data to the file, byte by byte.
        for (int i = 0; i < pfxByte.Length; i++)
          fileStream.WriteByte(pfxByte[i]);
        // Set the stream position to the beginning of the file.
        fileStream.Seek(0, SeekOrigin.Begin);
        // Read and verify the data.
        for (int i = 0; i < fileStream.Length; i++)
        {
          if (pfxByte[i] != fileStream.ReadByte())
          {
            fileStream.Close();
            return false;
          }
        }
        fileStream.Close();
      }
      if (isDelFromStore == true)
        store.Remove(x509);
    }
  }
  store.Close();
  store = null;
  storecollection = null;
  return true;
}

调用导出函数，代码如下：


	
DataCertificate.ExportToPfxFile(keyName, "Kiba518.pfx", "123456", true);

运行完导出函数后，我们打开Debug文件夹，可以看到证书已经被成功导出了，如下图：


X509Certificate2 x509 = X509Certificate2("Kiba518.pfx", "123456", X509KeyStorageFlags.Exportable);
string publickey = x509.PublicKey.Key.ToXmlString(false);//公钥获取
string privatekey = x509.PrivateKey.ToXmlString(true);//私钥获取

公钥私钥如下图所示：


//加密
public static string RSADecrypt(string xmlPrivateKey, string enptStr)
{
  RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
  provider.FromXmlString(xmlPrivateKey);
  byte[] rgb = Convert.FromBase64String(enptStr);
  byte[] bytes = provider.Decrypt(rgb, RSAEncryptionPadding.OaepSHA1);
  return new UnicodeEncoding().GetString(bytes);
}
//解密
public static string RSAEncrypt(string xmlPublicKey, string enptStr)
{
  RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
  provider.FromXmlString(xmlPublicKey);
  byte[] bytes = new UnicodeEncoding().GetBytes(enptStr);
  return Convert.ToBase64String(provider.Encrypt(bytes, RSAEncryptionPadding.OaepSHA1));
}

然后我们测试一下加密解密，测试函数如下。


public static void RsaTest()
{
  string myname = "my name is Kiba518!";
  Console.WriteLine($"内容：{myname}");
  string enStr = RSAEncrypt(publicKey, myname);
  Console.WriteLine($"加密字符串：{enStr}");
  string deStr = RSADecrypt(privateKey, enStr);
  Console.WriteLine($"解密字符串：{enStr}");
}

运行结果，加密解密成功，如下图所示：


//加密
public static String SubRSAEncrypt(string xmlPublicKey, string enptStr)
{
  RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
  provider.FromXmlString(xmlPublicKey);
  Byte[] bytes = Encoder.GetBytes(enptStr);
  int MaxBlockSize = provider.KeySize / 8 - 11;  //加密块最大长度限制

  if (bytes.Length <= MaxBlockSize)
    return Convert.ToBase64String(provider.Encrypt(bytes, false));

  using (MemoryStream PlaiStream = new MemoryStream(bytes))
  using (MemoryStream CrypStream = new MemoryStream())
  {
    Byte[] Buffer = new Byte[MaxBlockSize];
    int BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize);

    while (BlockSize > 0)
    {
      Byte[] ToEncrypt = new Byte[BlockSize];
      Array.Copy(Buffer, 0, ToEncrypt, 0, BlockSize);

      Byte[] Cryptograph = provider.Encrypt(ToEncrypt, false);
      CrypStream.Write(Cryptograph, 0, Cryptograph.Length);

      BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize);
    }

    return Convert.ToBase64String(CrypStream.ToArray(), Base64FormattingOptions.None);
  }
}
//解密
public static String SubRSADecrypt(string xmlPublicKey, string enptStr)
{
  RSACryptoServiceProvider provider = new RSACryptoServiceProvider();
  provider.FromXmlString(xmlPublicKey);
  Byte[] bytes = Convert.FromBase64String(enptStr);
  int MaxBlockSize = provider.KeySize / 8;  //解密块最大长度限制

  if (bytes.Length <= MaxBlockSize)
    return Encoder.GetString(provider.Decrypt(bytes, false));

  using (MemoryStream CrypStream = new MemoryStream(bytes))
  using (MemoryStream PlaiStream = new MemoryStream())
  {
    Byte[] Buffer = new Byte[MaxBlockSize];
    int BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);

    while (BlockSize > 0)
    {
      Byte[] ToDecrypt = new Byte[BlockSize];
      Array.Copy(Buffer, 0, ToDecrypt, 0, BlockSize);
      Byte[] Plaintext = provider.Decrypt(ToDecrypt, false);
      PlaiStream.Write(Plaintext, 0, Plaintext.Length);
      BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);
    }
    return Encoder.GetString(PlaiStream.ToArray());
  }
}

编写分段加密测试函数如下：


public static void SubRsaTest()
{
  string myname = "my name is Kiba518!my name is Kiba518!my name is Kiba518!my name is Kiba518!my name is Kiba518!my name is Kiba518!my name is Kiba518!";
  Console.WriteLine($"内容：{myname}");
  string enStr = SubRSAEncrypt(publicKey, myname);
  Console.WriteLine($"加密字符串：{enStr}");
  string deStr = SubRSADecrypt(privateKey, enStr);
  Console.WriteLine($"解密字符串：{deStr}");
}

运行结果，加密解密成功，如下图：