VPN Glossary: Every VPN Term Defined!

Welcome to our extensive VPN Glossary! This guide has compiled a comprehensive collection of VPN terms and their corresponding definitions.

Whether you’re new to the world of VPNs or a seasoned user, this resource will equip you with the knowledge needed to navigate the complex terminology and thoroughly understand VPN technology.

Virtual Private Network (VPN)

Virtual Private Network technology offers a secure, private, and virtual tunnel for safer internet access, resource sharing, and communication.

Source: Hui-hua, Z. (2002). VPN Technologys and its Application. Journal of Hubei Institute for Nationalities.

Advanced Encryption Standard (AES)

A widely-used encryption standard secures data through sophisticated algorithms, ensuring robust protection against cyber threats.

The AES algorithm is a symmetric block cipher that can encrypt (encipher) and decrypt (decipher) information. Encryption converts data to an unintelligible form called ciphertext; decrypting the ciphertext converts the data back into plaintext.

Source: Daemen, J. (2011). Advanced Encryption Standard. , 24. https://doi.org/10.1007/978-1-4419-5906-5_1206. 

Black Box Firewall

A network security device that monitors and controls traffic flow, protecting malicious activities. It can detect up to 70 different types of attacks.

It is designed to provide comprehensive network security, including acting as a broadband router and offering VPN capabilities for remote workers.

Source: Network Services, B. B. (2004). Black Box ® Firewall. Black Box; Black Box Corporation. http://www2.blackboxab.se/Datablad/10748.pdf 

Catapult Hydra

A high-performance VPN protocol developed by AnchorFree, the company behind the Hotspot Shield VPN service. It’s designed to provide superior performance and reliability compared to popular VPN protocols like IPSec/IKEv2 and OpenVPN.

Hydra is a low-power wireless protocol that guarantees robust communication despite arbitrary node and link failures, re-establishing efficient and reliable data exchange within seconds after a disruption.

Source: Biri, A., Forno, R., Kuonen, T., Mager, F., Zimmerling, M., & Thiele, L. (2023). Hydra: Concurrent Coordination for Fault-tolerant Networking. Proceedings of the 22nd International Conference on Information Processing in Sensor Networks. https://doi.org/10.1145/3583120.3587047. 

Cipher

A cipher is an algorithm or rule used to encrypt and decrypt data. It converts the original plaintext message into ciphertext that appears as random data. Modern ciphers are complex algorithms designed to be computationally secure against cryptanalysis.

Source: Wikipedia Contributors. (2019, January 15). Cipher. Wikipedia; Wikimedia Foundation. https://en.wikipedia.org/wiki/Cipher 

Certificate Authority (CA)

A trusted entity responsible for issuing digital certificates used to verify the identity of parties in a VPN connection. CAs play a crucial role in establishing secure SSL/TLS connections for VPNs.

Source: Awati, R. (2021, September). What is a certificate authority (CA)? SearchSecurity. https://www.techtarget.com/searchsecurity/definition/certificate-authority 

Content Filtering

The process of blocking or restricting access to specific websites, applications, or online content based on predefined criteria. VPNs can be used to bypass content filtering measures imposed by network administrators or governments.

Source: What Is Content Filtering? Definition, Types, and Best Practices – Spiceworks. (n.d.). Spiceworks Inc. Retrieved May 2, 2024, from https://www.spiceworks.com/it-security/network-security/articles/what-is-content-filtering-definition-types-and-best-practices/amp/ 

Dark Web

The hidden part of the internet accessed via specialized software is often associated with illegal activities and anonymity. 

The Dark Web allows for anonymous and encrypted communication and transactions, which has led to its association with illicit activities like the sale of drugs, weapons, stolen data, and other illegal goods and services.

However, the Dark Web also has legitimate uses, allowing dissidents and whistleblowers to communicate securely.

Source: Everything You Should Know About the Dark Web | Tulane School of Professional Advancement. (n.d.). Sopa.tulane.edu. https://sopa.tulane.edu/blog/everything-you-should-know-about-dark-web 

Deep Web

Deep web is also known as the invisible web, which standard search engines do not index. It includes databases, private networks, and restricted content. 

It is significantly larger than the surface web, with estimates suggesting that search engines index less than 1% of online content. 

The deep web is not inherently malicious but rather emphasizes privacy and relevance, making it less visible to search engines for everyday users.

Source: Frankenfield, J. (n.d.). Deep Web. Investopedia. https://www.investopedia.com/terms/d/deep-web.asp 

DD-WRT

A Linux-based open-source firmware that enhances the functionality and security of wireless routers, enabling advanced features like VPN support. 

The main benefit of DD-WRT is expanded capabilities and functionality, such as improved Wi-Fi range, bandwidth prioritization, VPN support, and more advanced firewall and security options.

Source: What is DD-WRT? | NordVPN. (2021, July 26). Nordvpn.com. https://nordvpn.com/blog/what-is-dd-wrt-router/  

Deep Packet Inspection (DPI)

DPI is an advanced network traffic analysis technique that examines the content of data packets, not just the header information. ISPs and governments use deep packet inspection (DPI) to analyze internet traffic at the packet level.   

Source: What Is Deep Packet Inspection (DPI)? (2024). Fortinet. https://www.fortinet.com/uk/resources/cyberglossary/dpi-deep-packet-inspection 

Domain Name System (DNS)

The Domain Name System (DNS) simplifies hostnames into IP addresses, making it easier for humans to remember website names and allowing servers to change IP addresses without losing their unique names.

It acts as the “phone book” of the internet, allowing users to access websites using memorable domain names rather than having to remember IP addresses.

Source: Голягин, А. (2017). Domain name system. https://doi.org/10.1201/9781315175577-5. 

Eavesdropping Attack

An unauthorized attempt to intercept and access data transmitted over a network compromising user privacy and security. 

These attacks can compromise confidentiality, cause financial losses and reputational damage, cause legal consequences, and violate privacy.

Source: What Is an Eavesdropping Attack & How to Prevent Them. (n.d.). RMail. Retrieved April 28, 2024, from https://rmail.com/glossary/eavesdropping-attack 

Encryption

Encryption is a key tool in cryptography, used for confidentiality, authentication, and digital signatures, among other applications. 

It’s the process of encoding data to prevent unauthorized access and ensure the confidentiality and integrity of information during transmission. 

Source: Zotos, K., & Litke, A. (2005). Cryptography and Encryption. arXiv: Category Theory. 

Encryption Key

Encryption algorithms use a string of characters to scramble and unscramble data, securing communication and data storage. 

Encryption and cryptography are fundamental to computer and communications security, transforming plaintext into ciphertext and vice versa.

Source: Berry, D. (2016). Encryption and Cryptography. , 1-4. https://doi.org/10.1002/9781118766804.wbiect253. 

Five Eyes Alliance

An intelligence-sharing agreement between five countries: the US, UK, Canada, Australia, and New Zealand. 

The Five Eyes has faced some criticism and debate around privacy issues and national security boundaries, especially after whistleblower Edward Snowden revealed its extensive surveillance capabilities.

Source: Haan, K. (2023, October 5). What Is The Five Eyes Alliance? – Forbes Advisor. Www.forbes.com. https://www.forbes.com/advisor/business/what-is-five-eyes/ 

Geo-blocking

Geo-blocking is a technology that limits user access to Internet content based on the user’s geographical location. Streaming services often restrict access to internet content based on the user’s geographic location. 

Anyone can bypass geo-blocking and unblock content using a Virtual Private Network (VPN). VPN allows users to unblock sites like Netflix, Amazon Prime, Hulu, BBC iPlayer, etc.

Source: Geo-blocking. (2021, April 30). Wikipedia. https://en.wikipedia.org/wiki/Geo-blocking 

IP address

A unique numerical label is assigned to devices connected to a computer network, enabling communication over the Internet. 

IP addresses are essential for the functioning of the Internet. They allow devices to communicate with each other and for data to be routed between them. They are also used to identify devices and networks on the Internet.

Source:  Yasar, K. (n.d.). What is an IP address (Internet Protocol Address)? | Definition from TechTarget. WhatIs.com. https://www.techtarget.com/whatis/definition/IP-address-Internet-Protocol-Address 

IPv4

IPv4 is the fourth version of the Internet Protocol, the primary addressing system used to route traffic across the Internet. It is composed of a 32-bit address and is a widely used variety of the Internet protocol and a standard for the Internet.

Source: IPv4 vs IPv6 – javatpoint. (n.d.). Www.javatpoint.com. https://www.javatpoint.com/ipv4-vs-ipv6 

IPv6

It’s the most recent version, composed of a 128-bit address. The latest version of the Internet Protocol (IPv4) was designed to accommodate the growing number of Internet-connected devices and address the limitations of IPv4.

Source: What is IPv6? (2020, May 1). GeeksforGeeks. https://www.geeksforgeeks.org/what-is-ipv6/ 

IP leak

IP leak is a security vulnerability that exposes a user’s real IP address, potentially compromising their online privacy and anonymity. 

It can happen when a user’s device or browser is not configured correctly to use a VPN or proxy server or when a VPN or proxy server malfunctions.

Source: Dahan, M. (2021, May 9). What are IP leaks and how can you prevent them? Comparitech. https://www.comparitech.com/blog/vpn-privacy/prevent-ip-leaks/ 

Jurisdiction

The legal authority or power a government or court exercises over a particular territory or set of circumstances is constitutionally based and defines the limits or territory within which a court or authority can exercise its power.

Source: jurisdiction | Definition, Examples, & Facts. (n.d.). Encyclopedia Britannica. https://www.britannica.com/topic/jurisdiction 

Key Exchange

It securely distributes encryption keys between parties for secure communication and data protection. It’s a crucial cryptographic process that allows two parties to exchange cryptographic keys securely, enabling them to share encrypted information and establish a secure communication channel.

Source: Villanueva, J. C. (2022, April 6). What Is A Key Exchange? Www.jscape.com. https://www.jscape.com/blog/key-exchange 

Kill switch

A VPN feature that automatically blocks internet traffic when the VPN connection drops prevents IP leaks and preserves user privacy. A kill switch is especially beneficial in hostile situations when privacy must be protected at all costs.

Source: What is a kill switch and how does it work? (n.d.). WhatIs.com. https://www.techtarget.com/whatis/definition/kill-switch 

Latency

The delay in data transmission over a network, measured in milliseconds, which can impact real-time applications like video streaming. 

In other words, latency is the time between a sender causing a change in a system’s change and its reception by the receiver.

Source: What is Latency? | Twilio. (n.d.). Www.twilio.com. https://www.twilio.com/docs/glossary/what-is-latency 

Lightway

A new VPN protocol developed by ExpressVPN is designed to offer high performance while maintaining robust security. 

As ExpressVPN claims, It is engineered to be lightweight and efficient, delivering speedier, more secure, and more reliable performance. Lightway runs faster, consumes less battery power, and is easier to audit and maintain. 

Source: Lightway: A VPN Protocol by ExpressVPN | ExpressVPN. (n.d.). Www.expressvpn.com. Retrieved May 2, 2024, from https://www.expressvpn.com/lightway 

Logging

Logging is the practice of recording and storing user activity data such as IP address, browsing history, device ID, email address, and other info, which can compromise user privacy if accessed by third parties. 

Source: What Dirt Does Your VPN Have on You? VPN Logging Explained. (n.d.). PCMAG. Retrieved May 2, 2024, from https://www.pcmag.com/explainers/what-dirt-does-your-vpn-have-on-you-vpn-logging-explained 

Man-in-the-middle 

A type of cyberattack where an attacker intercepts and alters communication between two parties, compromising data integrity and security. 

There are multiple types of MITM attacks like DNS spoofing, IP spoofing, HTTPS spoofing, Email Hijacking, Wi-Fi eavesdropping etc.

Source: Magnusson, A. (2024, January 29). Man-in-the-Middle (MITM) Attack: Definition, Examples & More | StrongDM. Discover.strongdm.com. https://www.strongdm.com/blog/man-in-the-middle-attack 

No Logs Policy

A privacy policy adopted by some VPN providers ensures that no user activity or connection data is recorded or stored. 

Source: Some VPNs use strict no-logging policies to prevent privacy breaches and ensure privacy and security for the users.

Obfuscation

The process of concealing or disguising data or network traffic to evade censorship, surveillance, or detection by third parties. Many popular VPNs offer obfuscated servers integrated with TOR for extra security. When you use an obfuscated server the observer cannot detect if you’re using a VPN or not securing you from prying eyes.

Source: What is Obfuscation? – PreEmptive. (2023, December 8). Www.preemptive.com. https://www.preemptive.com/what-is-obfuscation/ 

OpenVPN

An open-source VPN protocol widely used for its flexibility, security, and compatibility across various platforms and devices. OpenVPN delivers strong security and optimal speed for all kinds of internet activities.

Source: OpenVPN. (2021, February 26). Wikipedia. https://en.wikipedia.org/wiki/OpenVPN 

Perfect Forward Secrecy

A cryptographic feature that ensures previously captured encrypted data cannot be decrypted, even if the encryption key is compromised.

Source: Saha, P. (2023, September 27). All you need to know about Perfect Forward Secrecy.https://www.encryptionconsulting.com/all-you-need-to-know-about-perfect-forward-secrecy/ 

Ping

A utility used to test the connectivity and latency between two devices on a network by sending and receiving data packets. Ping is calculated in milliseconds (ms). 

For example, if your internet connection speed is 45ms that means it takes 45 milliseconds to send and receive data packets in your computer.

Source: Zola, A. (2021, July). What Is a Ping and How Does it Work? TechTarget. https://www.techtarget.com/searchnetworking/definition/ping 

Protocol

A set of rules and standards that govern data communication and transmission over a network or the internet. VPNs have multiple protocols like WireGuard, OpenVPN, Shadowsocks, OpenConnect, IPSec, L2TP etc.

Source: 6 Common VPN Protocols Explained – Forbes Advisor. (n.d.). Www.forbes.com. https://www.forbes.com/advisor/business/software/vpn-protocols/ 

Proxy

A server that acts as an intermediary between a user’s device and the internet, potentially enhancing privacy and security. 

It enhances privacy, security, and performance by simplifying or controlling the complexity of requests, providing benefits like load balancing, privacy, and security.

Source: Wikipedia Contributors. (2019b, May 17). Proxy server. Wikipedia; Wikimedia Foundation. https://en.wikipedia.org/wiki/Proxy_server 

Public Wi-Fi

Wireless internet access points are available in public places like airports, cafes, and hotels, which can pose security risks if not used properly.

Hackers can perform cyber attacks like man-in-the-middle attack to intercept and steal your data, sensitive information like credit card details, passwords, etc.

Source: What is Public Wi-Fi? How to use Public Wi-Fi safely? (n.d.). Fortinet. https://www.fortinet.com/resources/cyberglossary/vpn-wifi 

Split tunneling

A VPN feature that allows users to selectively route traffic through the VPN tunnel or a direct internet connection, offering flexibility and control. 

Split tunneling allows you to select which application you want to use with VPN and which applications you want to use with VPN and which you don’t.

Source: Hiley, C. (2021, February 13). What Is VPN Split Tunneling? When Do You Need It? CyberNews. https://cybernews.com/what-is-vpn/split-tunneling/ 

StrongSwan

An open-source VPN solution that implements the IPsec protocol suite for secure communication over IP networks.

It fully implements the Internet Key Exchange (IKEv2) protocol and supports certificate revocation lists and the Online Certificate Status Protocol (OCSP).

Source: strongSwan project. (2012). strongSwan – IPsec VPN for Linux, Android, FreeBSD, Mac OS X, Windows. Strongswan.org. https://www.strongswan.org/ 

Throttling

The intentional slowing down of internet speeds by ISPs or other entities, often to manage network congestion or enforce data caps.

For example, your ISP may throttle down your internet speed if they detect you’re consuming too much bandwidth or applying intensive games. VPNs can help you bypass ISP throttling and unlock the full potential of your internet connection.

Tor (Onion Network)

A free, open-source software that enables anonymous communication by routing internet traffic through a global network of relays, enhancing user privacy.

TOR is so strong that it;s used by cybersecurity professionals, secret agencies, militaries, and law enforcement officials for secure communications.

Source: The Tor Project | Privacy & Freedom Online. (n.d.). Torproject.org. https://www.torproject.org/download/ 

Tunnel

A secure, encrypted connection between two points over a public network enables private data transmission. It serves to protect the user’s online activity and data.

Source: Danao, M. (2023, December 22). What Is A VPN Tunnel And How Does It Work? Forbes Advisor INDIA. https://www.forbes.com/advisor/in/business/what-is-vpn-tunnel/ 

VPN Client

Software installed on a device that establishes a secure connection to a VPN server, enabling private and encrypted internet access.

VPN clients are usually cross-platform and allow the user to connect to VPN networks from any device on demand. There are three types of clients: system-based or native, protocol based, and service-based client.

Source: Download VPN client just in a few clicks | NordVPN. (2021, July 9). Nordvpn.com. https://nordvpn.com/vpn-client/ 

VPN Server

A remote server that acts as the endpoint for VPN connections, facilitating secure and private internet access for clients. When you connect to a VPN connection it connects you to a secure server located in a different location and secures your data.

Source: Inc, P. I. A. (n.d.). The Fastest VPN Servers with Worldwide Locations | PIA VPN. Www.privateinternetaccess.com. Retrieved May 2, 2024, from https://www.privateinternetaccess.com/vpn-server 

WebRTC

A technology that enables real-time communication between web browsers and devices, potentially exposing a user’s true IP address. 

This technology facilitates rich, high-quality real-time communication applications for browsers, mobile platforms, and IoT devices, enabling communication through a common set of protocols.

Source: Livestorm. (n.d.). What is Web RTC | Livestorm. Livestorm.co. https://livestorm.co/webinar-glossary/webrtc 

WireGuard

A modern, high-performance VPN protocol designed for simplicity, speed, and strong security, it is gaining popularity among VPN providers.

It was designed with the goals of ease of use, high-speed performance, and a small attack surface, aiming to be simpler and more efficient than IPsec and OpenVPN.

Source: Donenfeld, J. A. (2015). WireGuard: fast, modern, secure VPN tunnel. Wireguard.com. https://www.wireguard.com/