A wireless communication system comprises two communication units (101, 03) which exchange public key identification data using both Near Field Communication (NFC) and Wi-Fi. Comparators (213) compare the public key identification data received over NFC to that received over Wi-Fi. If they do not match, communication controllers (203, 303) terminate a Wi-Fi communication, and specifically may terminate a secure Wi-Fi communication setup. If the public key identification data match, the communication controllers (203, 303) determine matching session keys and network keys from the public key identification data. The approach utilizes a full two-way device authentication based on two-way NFC communications to provide increased security and robustness to e.g. man-in-the-middle attacks.