将非对称算法私钥和公钥与 RSA C# 一起使用

我有两个包含 RSA 私钥和 RSA 公钥的 AsymmetryAlgorithm 对象。私钥是从 Windows-MY 密钥库中检索的，公钥是从用户的证书中检索的。如何在 C# 中将这些密钥与 RSACryptoServiceProvider 一起使用 RSA 算法来加密数据？换句话说，我如何指定我想要使用我已经拥有的密钥？

#region "RSA Encrypt/Decrypt"  
public string RSAEncrypt(string str, string publicKey)  
{  
  //---Creates a new instance of RSACryptoServiceProvider---  
  try {  
     RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();  
     //---Loads the public key---  
     RSA.FromXmlString(publicKey);  
     byte[] EncryptedStr = null;  

     //---Encrypts the string---  
     EncryptedStr = RSA.Encrypt(ASCII.GetBytes(str), false);  
     //---Converts the encrypted byte array to string---  
     int i = 0;  
     System.Text.StringBuilder s = new System.Text.StringBuilder();  
     for (i = 0; i <= EncryptedStr.Length - 1; i++) {  
         //Console.WriteLine(EncryptedStr(i))  
         if (i != EncryptedStr.Length - 1) {  
             s.Append(EncryptedStr[i] + " ");  
         } else {  
             s.Append(EncryptedStr[i]);  
         }  
     }  

     return s.ToString();  
   } catch (Exception err) {  
     Interaction.MsgBox(err.ToString());  
   }  
}  

public string RSADecrypt(string str, string privateKey)  
{  
  try {  
     //---Creates a new instance of RSACryptoServiceProvider---  
     RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();  
     //---Loads the private key---  
     RSA.FromXmlString(privateKey);  

     //---Decrypts the string---  
     byte[] DecryptedStr = RSA.Decrypt(HexToByteArr(str), false);  
     //---Converts the decrypted byte array to string---  
     System.Text.StringBuilder s = new System.Text.StringBuilder();  
     int i = 0;  
     for (i = 0; i <= DecryptedStr.Length - 1; i++) {  
         //Console.WriteLine(DecryptedStr(i))  
         s.Append(System.Convert.ToChar(DecryptedStr[i]));  
     }  
     //Console.WriteLine(s)  
     return s.ToString();  
  } catch (Exception err) {  
     Interaction.MsgBox(err.ToString());  
  }  
}  
#endregion 

公钥 (arg) 应如下所示： yNi8BvATA77f+/6cU6z[...]9VULgU=模数> AQAB指数> 密钥值>

私钥 (arg) 应如下所示： yNi8BvATA77f+/6cU6z[...]9VULgU=模数> AQAB指数>

8ZlZPmko3sam9pvD/l[...]ba0MWLjj9dyUMvmTQ6L8m9IQ==