Talking in the open (Wi-fi Privacy)

WPA3 is coming fast and I'm excited to see how quickly client devices adopt the benefits of the incorporated security concepts. Using SAE instead of PSK is a fascinating change. Perfect forward secrecy is exciting, especially in when offline attacks of PSK protected data became easier using hashcat. (See https://hashcat.net/forum/thread-7717.html August 4, 2018). There are now a lot of new things to learn about.

Obviously the two key important factors with WPA3 (as they are in WPA2) are the authentication of users trying to access the network and privacy of data using encryption. We use these features to protect the system and the information between sent across it because Wi-Fi operates in the air and physical security is pretty much always an impossible factor. Along side the announcement of the upcoming availability of WPA3 was news of another capability called Opportunist Wireless Encryption (OWE). This brings a capability that allows for privacy over open wireless networks. To date all traffic transmitted to or from an open SSID is sniffable and does not require decryption. A MacBook running Wireshark is all you need to to catch the human readable wireless frames.

OWE is described in RFC 8110 which was written by Dan Harkins (Aruba) and Warren Kumari (Google).

I kept hearing about the Diffie-Hellman exchange and understood that it was the function that allowed two things (a wireless client and Access Point in this case) to communicate just enough information between each other to derive a complex key. It happens in such a way that if any other party was to intercept the communication they could not derive the key. This is cool. Diffie-Hellman is used in a lot of technology we take advantage of day to day. We take advantage of the Diffie-Hellman exchange without even realising how important it is to cryptography and privacy of our data.

Written by Matt Sutherland