Shared key authentication is a WEP method that verifies whether a wireless client possesses the static WEP key configured on both the client and access point. WEP is obsolete and no longer secure. section 20.1.2 section 20.5
The authentication exchange works as follows:
- The client sends an authentication request. section 20.1.2
- The access point returns an unencrypted challenge phrase. section 20.1.2
- The client encrypts the challenge with the shared WEP key and returns the ciphertext. section 20.1.2 section 20.5
- The access point decrypts the response and compares it with the original challenge; a match verifies possession of the key. section 20.1.2
Challenge exchange
Figure 20.3 depicts the client and access point exchanging a challenge phrase, with the client encrypting it and the access point decrypting and checking it.
