To fully appreciate why WPA3-Personal is immune to dictionary attacks, we must dive into the Dragonfly mechanism (the engine of SAE). It moves the security from a simple hash verification to a complex elliptic curve problem.
The Dragonfly handshake consists of two distinct phases. First, the 'Commit' phase, where both parties exchange scalar and element values derived from the password. Second, the 'Confirm' phase, where they prove they both possess the same key.
The key innovation is that the password is used to pick a point on a curve, and that point is used to create a temporary key—the password itself is never sent.
# Conceptual Dragonfly Commit
# 1. Hash password to find a point P on the curve (Hunting and Pecking)
# 2. Generate a random private scalar 'r'
# 3. Public Element = r * P
# 4. Send (r, Public Element) to peer
# The peer does the same, and through DH, they find a shared secretIf the password is wrong, the parties will derive different points on the curve, and the 'Confirm' phase will fail. Crucially, an observer sees only random-looking points, not the password's hash.
Elliptic Curve Cryptography is CPU-intensive. An attacker could flood an AP with fake 'Commit' messages to crash the router's CPU.
To prevent this, WPA3 introduces 'Anti-Clogging Tokens.' If the AP is under load, it refuses to process a Commit until the client returns a token, proving the client can at least receive and echo a packet.
| Phase | Action | Data Exchanged | Purpose |
|---|---|---|---|
| Hunting & Pecking | Internal | Password $ o$ Curve Point | Derive base point |
| Commit | Exchange | Scalar + Element | Agree on session secret |
| Confirm | Verification | Hash of Secret | Verify both have the password |
| Clogging | Mitigation | Token | Prevent CPU exhaustion |
Because the Dragonfly handshake provides an authenticated key exchange, an attacker cannot perform an offline attack. To guess the password, they must interact with the AP for every single guess, making a dictionary attack practically impossible.
Dragonfly implementation errors (like the Dragonblood vulnerability) can re-introduce side-channel leaks, emphasizing the need for updated firmware.
Verify exercises to earn ★ 210 XP and unlock next lab level.