C#.NET 读取PFX私钥证书并导出PEM格式私钥

项目nuget引用 BouncyCastle。

读取证书

X509Certificate2 x509 = new X509Certificate2(lblPfxPath.Text, txtPfxPwd.Text.Trim(), X509KeyStorageFlags.Exportable);
                //x509.PrivateKey.ToXmlString(true);//xml格式私钥
                txtPemPrivateKey.Text = xmlToPem((RSACryptoServiceProvider)x509.PrivateKey);

转成PEM私钥（PKCS1模式）。

public string xmlToPem(RSACryptoServiceProvider rsa2)
        {
            string priKey = null;
            var p = rsa2.ExportParameters(true);

            var key = new RsaPrivateCrtKeyParameters(
                new BigInteger(1, p.Modulus), new BigInteger(1, p.Exponent), new BigInteger(1, p.D),
                new BigInteger(1, p.P), new BigInteger(1, p.Q), new BigInteger(1, p.DP), new BigInteger(1, p.DQ),
                new BigInteger(1, p.InverseQ));

            using (TextWriter sw = new StringWriter())
            {
                var pemWriter = new Org.BouncyCastle.OpenSsl.PemWriter(sw);
                pemWriter.WriteObject(key);
                pemWriter.Writer.Flush();
                priKey = sw.ToString();
            }

            return priKey;
        }

xml格式的直接：x509.PrivateKey.ToXmlString(true);