从BouncyCastle X509证书获取私钥？C#

using System;
using System.IO;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.OpenSsl;
using Org.BouncyCastle.Pkcs;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.X509;

public class BouncyCastleX509
{
    public static AsymmetricKeyParameter GetPrivateKey(string certificatePath, string password)
    {
        using (var reader = File.OpenText(certificatePath))
        {
            var pemReader = new PemReader(reader, new PasswordFinder(password));
            var pkcs12 = (AsymmetricCipherKeyPair)pemReader.ReadObject();
            return pkcs12.Private;
        }
    }

    private class PasswordFinder : IPasswordFinder
    {
        private readonly string _password;

        public PasswordFinder(string password)
        {
            _password = password;
        }

        public char[] GetPassword()
        {
            return _password.ToCharArray();
        }
    }
}

Install-Package BouncyCastle