Wireless Security Protocols: WPA, WPA2 and WPA3

What it is

Wireless security authenticates who may connect and encrypts the data, and WPA, WPA2 and WPA3 do this with growing strength.

Radio waves travel through walls and out of the building. Anyone nearby can receive a Wi-Fi signal, so without protection they can read the traffic or join the network.

The security protocols for Wi-Fi have improved over time. This topic covers WPA, WPA2 and WPA3, and mentions the earlier WEP for comparison.

How it works

Each generation fixed the weaknesses of the one before it, and each comes in a Personal and an Enterprise mode.

The history

WEP (Wired Equivalent Privacy) was the first attempt. It used a weak implementation of the RC4 cipher, and its flaws allow the key to be recovered in minutes. It must not be used.

WPA (Wi-Fi Protected Access) was a quick fix for WEP's problems, designed to run on the same hardware. It used TKIP with RC4, which was a big improvement but is itself now considered weak.

WPA2 replaced TKIP with AES, a strong, modern cipher, through a mode called CCMP. For many years, it has been the standard.

WPA3 is the newest, and it improves both the key exchange and the protections around it.

Personal and Enterprise modes

WPA2 and WPA3 each come in two modes, which differ in how users authenticate.

• Personal (PSK): everyone uses one pre-shared key, a passphrase. It is simple, and suited to homes and small offices. The weakness is that the key is shared. If it leaks, or an employee leaves, it must be changed everywhere, and all users can in principle see the same key material.
• Enterprise (802.1X): each user authenticates individually, through a RADIUS server, with their own credentials or a certificate. Each session gets its own unique keys. It suits organisations, and lets you remove a single user without disturbing the others.

Comparing the protocols

WPA3-Personal uses AES with CCMP and 128-bit keys. WPA3-Enterprise can use CCMP too, and its optional 192-bit mode uses AES with GCMP and 256-bit keys.

What WPA3 adds

SAE (Simultaneous Authentication of Equals) replaces the pre-shared key handshake in WPA3-Personal. In WPA2-PSK, an attacker who captures the handshake can try millions of passphrase guesses offline, at their own pace.

With SAE, each guess requires interaction with the network, so offline guessing is blocked. Even if the passphrase is leaked later, traffic that was recorded earlier cannot be decrypted. This property is called forward secrecy.

Protected management frames (PMF) are required in WPA3. They stop attackers from forging messages that kick clients off the network, known as deauthentication attacks.

Stronger Enterprise options are available, including a higher strength mode intended for sensitive environments.

A related feature, Enhanced Open (based on OWE), gives encryption even on networks that have no password, such as a coffee shop. Each client gets its own encryption key, so other users cannot read its traffic, although the network still does not authenticate users.

Transition mode

When a network has both old and new devices, an access point can run in a transition mode, accepting both WPA2 and WPA3 clients on the same name. It allows gradual migration, but the network is only as secure as its weakest allowed method.

Practical advice

• Use WPA3 where all clients support it, and WPA2 with AES where they do not.
• Never use WEP, and avoid TKIP.
• Use a long, random passphrase for PSK networks.
• Use Enterprise mode when you need individual accountability.
• Keep access point firmware up to date.