使用C#.Net通过FTPS(SSL/TLS)传输文件

Question

我正在编写一个通过FTP站点同步文件的应用程序.现在它正在通过常规FTP连接,但现在我们的IT人员希望通过安全的FTPS连接进行设置.

他们为我提供了一个*.cr_证书文件.如果我在记事本中打开文件,我会看到类似的东西(但真正的键显然不是foobar).

-----BEGIN RSA PRIVATE   
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
FOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBARFOOBAR    
-----END CERTIFICATE-----

如何使用此证书文件连接到FTPS服务器以上载和下载文件？原谅我,但我对涉及通过网络传输文件,安全连接,证书,公钥,私钥等等的任何事情都很陌生......等等......

我想我想使用FtpWebRequest对象并将EnableSsl属性设置为true.但我不确定这个证书文件在哪里发挥作用.

Answer 1

如果您正在使用FtpWebRequest类,则只需在请求设置中添加一些内容即可.一定要包括using System.Security.Cryptography.X509Certificates;声明.

    FtpWebRequest request = (FtpWebRequest)WebRequest.Create(ftpUrl);
    request.Credentials = new NetworkCredential(userName, password);

    request.EnableSsl = true;
    //ServicePointManager.ServerCertificateValidationCallback = ServicePointManager_ServerCertificateValidationCallback;

    X509Certificate cert = X509Certificate.CreateFromCertFile(@"C:\MyCertDir\MyCertFile.cer");
    X509CertificateCollection certCollection = new X509CertificateCollection();
    certCollection.Add(cert);

    request.ClientCertificates = certCollection;

此外,如果您在证书生成异常时遇到问题,则可能需要实现自己的证书验证回调方法,以便与ServicePointManager.ServerCertificateValidationCallback属性一起使用.这可以像总是返回true一样简单,也可以像我用来调试那样复杂:

    public static bool ServicePointManager_ServerCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
    {
        bool allowCertificate = true;

        if (sslPolicyErrors != SslPolicyErrors.None)
        {
            Console.WriteLine("Accepting the certificate with errors:");
            if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateNameMismatch) == SslPolicyErrors.RemoteCertificateNameMismatch)
            {
                Console.WriteLine("\tThe certificate subject {0} does not match.", certificate.Subject);
            }

            if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateChainErrors) == SslPolicyErrors.RemoteCertificateChainErrors)
            {
                Console.WriteLine("\tThe certificate chain has the following errors:");
                foreach (X509ChainStatus chainStatus in chain.ChainStatus)
                {
                    Console.WriteLine("\t\t{0}", chainStatus.StatusInformation);

                    if (chainStatus.Status == X509ChainStatusFlags.Revoked)
                    {
                        allowCertificate = false;
                    }
                }
            }

            if ((sslPolicyErrors & SslPolicyErrors.RemoteCertificateNotAvailable) == SslPolicyErrors.RemoteCertificateNotAvailable)
            {
                Console.WriteLine("No certificate available.");
                allowCertificate = false;
            }

            Console.WriteLine();
        }

        return allowCertificate;
    }

Answer 2

本文通过源代码解释了如何做到这一点。

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本文的目的是创建一个安全模式下的 C# FTP 客户端，所以如果你对 FTPS 不太了解，我建议你看看这个：FTPS。

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在.NET Framework中，要以FTPS方式上传文件，我们一般使用FtpWebRequest类，但是不能发送带有引号参数的命令，而且即使在网上搜索也找不到安全的具体示例。 C# FTP 客户端。

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它\xe2\x80\x99s 出于这些原因我决定创建这篇文章。

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