SEO Proxy Hijacking

A firewall is responsible for filtering packets of traffic. For example, it blocks access to the Internet for certain applications. There are many more options for using a proxy. But if you install special software, it can also be used for such purposes.

Technically, ISP can block only some intermediary servers by IP-addresses. But it's impossible to block absolutely all VPN-servers, because there are so many of them and their addresses are constantly changing. Accordingly, in this case, you just need to use another VPN-server.

There are HTTP proxy, FTP proxy, SOCKS proxy, SMTP proxy, CGI proxy. They differ only in the data transmission protocol used and the purpose for which they are used. For example, SMTP proxy allows you to organize a secure server for e-mail.

Bouncy Castle is a popular cryptography library in C#. If you want to parse and extract Certificate Signing Request (CSR) extensions using Bouncy Castle, you can follow these steps

Add Bouncy Castle Library

First, make sure you have the Bouncy Castle library added to your project. You can do this via NuGet Package Manager:

Install-Package BouncyCastle

Parse CSR:

Use Bouncy Castle to parse the CSR. The following code demonstrates how to parse a CSR from a PEM-encoded string:

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

class Program
{
    static void Main()
    {
        string csrString = File.ReadAllText("path/to/your/csr.pem");

        Pkcs10CertificationRequest csr = ParseCSR(csrString);

        // Now you can work with the parsed CSR
    }

    static Pkcs10CertificationRequest ParseCSR(string csrString)
    {
        PemReader pemReader = new PemReader(new StringReader(csrString));
        object pemObject = pemReader.ReadObject();

        if (pemObject is Pkcs10CertificationRequest csr)
        {
            return csr;
        }

        throw new InvalidOperationException("Invalid CSR format");
    }
}

Extract Extensions:

Once you have the CSR parsed, you can extract extensions using the GetAttributes method. Extensions in a CSR are typically stored in the Attributes property. Here's an example:

foreach (DerObjectIdentifier oid in csr.CertificationRequestInfo.Attributes.GetOids())
{
    Attribute attribute = csr.CertificationRequestInfo.Attributes[oid];

    // Work with the attribute, e.g., check if it's an extension
    if (oid.Equals(PkcsObjectIdentifiers.Pkcs9AtExtensionRequest))
    {
        X509Extensions extensions = X509Extensions.GetInstance(attribute.AttrValues[0]);

        // Now you can iterate over extensions and extract the information you need
        foreach (DerObjectIdentifier extOID in extensions.ExtensionOids)
        {
            X509Extension extension = extensions.GetExtension(extOID);
            // Process the extension
        }
    }
}

Modify the code according to your specific requirements and the structure of your CSR. The example assumes a basic structure, and you may need to adapt it based on your CSR format and the extensions you're interested in.

The main scenarios for using a proxy server: bypassing blocking, hiding the real IP, protection of confidential data when connecting to public WiFi access points, interaction with blocked applications, connection to closed portals, forums (which operate only in one country, region).