VPN Explained - How It Protects Your Privacy Online

About 2 min read

A VPN (Virtual Private Network) is a technology that builds an encrypted virtual private line (tunnel) over the internet to exchange data securely. Even on untrusted networks such as public Wi-Fi, using a VPN protects the contents of your communication from third parties. It is used for a wide range of purposes, from corporate remote access to personal privacy protection.

The Difference Between a VPN and SSL/TLS

Both VPN and SSL/TLS are technologies that encrypt communication, but the scope of what they protect differs. SSL/TLS encrypts specific communication between a browser and a server (HTTPS), whereas a VPN encrypts all communication from a device through a tunnel. For example, a VPN can also protect the communication of applications that do not support HTTPS as well as DNS queries. On the other hand, SSL/TLS can be used with just a browser without additional software, and it also performs authentication for each website (certificate verification). In practice, it is common to use both together: by carrying HTTPS communication inside a VPN tunnel, double encryption is achieved.

How a VPN Works

A VPN creates an encrypted tunnel between the user's device and the VPN server. Because all communication data passes through this tunnel, its contents cannot be read even if intercepted along the way. Major protocols include OpenVPN, WireGuard, and IKEv2/IPsec. WireGuard is a relatively new protocol characterized by a simple design and fast connections. As of 2024, many VPN services have adopted WireGuard as their standard protocol. By routing through the VPN server, the source IP address is also concealed.

Confirming That the Protection Is Still Holding

Once the path is in place, the practical question becomes how to confirm that the protection is still holding. First, protection exists only while the path is established, and the moments when the path drops arrive in ways the user does not see: when the connection switches to a different network, when the device wakes from standby, when the session reaches its expiry. All of these happen while nobody is operating anything. Whether traffic is protected therefore depends not on what is displayed on screen but on how it was decided in advance whether to stop or to pass traffic when the path drops. Second, that decision carries a cost in both directions. Configuring it to stop when the path drops preserves protection, but work also stops for as long as the path is unavailable. Configuring it to pass anyway lets work continue, but unprotected traffic occurs during that window, and the fact that it occurred is hard to establish afterwards. In a design that funnels all traffic through a single path, this choice applies to everything at once, so which option is correct is not settled by the technology; it becomes a comparison between how much a stoppage costs and how much exposure costs. Third, when comparing speed before and after a change, the difference has no meaning unless the measurement conditions are fixed. Path speed varies with congestion, distance, and time of day, so a difference measured before and after a switch mixes in factors other than the switch itself. An impression that things got faster cannot be separated into an effect of the new configuration and an effect of the conditions under which it was measured until both endpoints and the time of measurement are aligned and the measurement is repeated.

Communication Path Diagram

Practical Considerations and Pitfalls

When choosing a VPN service, it is important to select one that adheres to a no-logs policy (a policy of not storing communication records). Be cautious, as free VPN services may collect and sell your communication data. A common misconception is the idea that "using a VPN makes you completely anonymous," but the VPN provider knows your source IP and may disclose it if there is a legal request. In addition, a VPN cannot prevent access to phishing sites or malware infections. The security of the VPN account itself is also important, so protect your account with a strong, random password and two-factor authentication.