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Choosing the Right Extensible Authentication Protocol For Your Network


Authentication protocols play a significant role in securing end-to-end connections and wireless communications across devices and applications. The extensible authentication protocol is one such protocol framework that offers a wide array of authentication mechanisms. Because of its versatile nature and the 40 different methods defined within, the extensible authentication protocol can perform multiple authentications without pre-negotiating a specific one. This article will examine extensible authentication protocols and their different methods, features, and advantages.

What is an Extensible Authentication Protocol?

An Extensible Authentication Protocol (EAP) is a Local Area Network (LAN) communication and point-to-point (P2P) wireless connecting framework. It helps authenticate clients, computers, or wireless LAN systems to the internet. With Extensible Authentication Protocol, networks can authenticate dial-up connections and LAN networks. EAP ideally works on encrypted networks to transmit identifying information required for network authentication. 

Experts consider it a framework because it offers a range of authentication mechanisms for OTPs, token cards, digital certificates, smart cards, and public-key encryption authentication. The various authentication methods within this framework protect the portal or a network from unauthorized users. These methods ask for authentication key(s) or passwords to allow users to access network resources. Over the years, multiple Extensible Authentication Protocol methods and techniques have been standardized, including vendor-specific ones.

Features of an Extensible Authentication Protocol

Extensibility is the key attribute that differentiates this authentication protocol from the rest. Here are some of its popular features:

  • It acts as a framework under which various authentication methods operate.

  • It is easily extensible and adaptable to future security authentication needs.

  • It is versatile and can function in different authenticating scenarios, such as smart cards, OTPs, and asymmetric encryption.

  • It is simple- enterprises can use it to adapt to corporate guidelines and privacy needs.

How does Extensible Authentication Protocol operate?

The Extensible Authentication Protocol uses the 802.1x standard for authenticating in Wireless LAN or local area networks. It acts as a response-based authentication protocol that enables a conversation between the wireless/wired client and the authenticating server via an authenticator (such as a wireless access point). Enterprises leveraging this protocol must determine what Extensible Authentication Protocol type to employ based on requirements.

Here are the basic steps on how it operates.

  1. The client will request a connection through a wired or wireless network through an access point (AP). This AP can perform data transmission in either direction.

  2. Then, the AP requests user identification and transmits the authenticated data to the authentication server.

  3. The server then asks the AP to provide validation proof about the identifiable information.

  4. Once the AP receives the user verification, it sends the verification information back to the authentication server.

  5. Once this authentication and verification process completes, the user gets connected to the requested network.

Note: The process may vary depending on the type of EAP used.

Different methods of Extensible Authentication Protocol and their advantages

Depending on the various authentication approaches, Extensible Authentication Protocol methods can vary. While some methods come under standard Extensible Authentication Protocol, others are proprietary.

1. Extensible Authentication Protocol-Transport Layer Security (EAP-TLS)

It provides mutual authentication where both the server and the client must have the same certificate to achieve the authentication. This method generates session-based and user-based Wired Equivalent Privacy (WEP) keys.


  • Works well inside a secure SSL tunnel.

  • Since it leverages a mutual certificate for authentication, the process is simple than others.

2. Extensible Authentication Protocol-Tunneled Transport Layer Security (EAP-TTLS)

Like EAP-TLS, it also offers mutual certificate-based authentication. But rather than the server and the client needing the certificate, only the server needs the certificate here. 


  • It does not expose the user's identity.

  • Works well inside a secure SSL tunnel.

3. Lightweight-Extensible Authentication Protocol (LEAP)

It is Cisco's proprietary Extensible Authentication Protocol method, where the server sends the client a random authentication challenge. In return, the client responds with a hashed password. Once the authentication method finishes, the client asks for the password to the server. 


  • Enterprises use LEAP for P2P connections and wireless networks.

4. Protected Extensible Authentication Protocol (PEAP)

It is another Cisco proprietary Extensible Authentication Protocol method that is more secure than LEAP. It creates an encrypted TLS tunnel so that client can authenticate through it.


  • It is more secure and used for 802.11 WLAN authentications.

5. Extensible Authentication Protocol-Message Digest 5 (EAP-MD5)

It provides authentication in one-way rather than mutual (between the server and the client). It does not supply per-session WEP keys. Hence, it is prone to cyber threats.


  • It is compatible with old endpoints and legacy network systems.


Extensible Authentication Protocol offers a robust authentication system to keep the network safe. It is important to choose the right method depending on the type of network and security requirements. With the increasing number of cyber threats, it is essential to have a secure authentication system in place.

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