csharp 读取本地公钥PEM、私钥PEM文件，加载为XML格式

可以使用 BouncyCastle 库来读取本地公钥PEM、私钥PEM文件，并将其加载为XML格式。以下是示例代码：

using System;
using System.IO;
using System.Security.Cryptography;
using System.Xml;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.OpenSsl;

class Program
{
    static void Main(string[] args)
    {
        string publicKeyPath = "public_key.pem";
        string privateKeyPath = "private_key.pem";

        // Read public key
        AsymmetricKeyParameter publicKeyParam;
        using (var reader = File.OpenText(publicKeyPath))
        {
            publicKeyParam = (AsymmetricKeyParameter)new PemReader(reader).ReadObject();
        }

        // Convert public key to XML format
        var rsa = (RSA)RSA.Create();
        rsa.ImportParameters(DotNetUtilities.ToRSAParameters((RsaKeyParameters)publicKeyParam));
        var publicKeyXml = rsa.ToXmlString(false);

        // Read private key
        AsymmetricCipherKeyPair keyPair;
        using (var reader = File.OpenText(privateKeyPath))
        {
            keyPair = (AsymmetricCipherKeyPair)new PemReader(reader).ReadObject();
        }

        // Convert private key to XML format
        rsa = (RSA)RSA.Create();
        rsa.ImportParameters(DotNetUtilities.ToRSAParameters((RsaPrivateCrtKeyParameters)keyPair.Private));
        var privateKeyXml = rsa.ToXmlString(true);

        // Print public and private keys in XML format
        Console.WriteLine("Public key in XML format:");
        Console.WriteLine(publicKeyXml);
        Console.WriteLine();
        Console.WriteLine("Private key in XML format:");
        Console.WriteLine(privateKeyXml);
    }
}

注意：BouncyCastle 库需要通过 NuGet 安装。