The signal in wireless networks is dispersed through air freely, unlike signal in wired networks. It is necessary to have the best as possible security protocol in order to achieve privacy and integrity of sent data. First of WLAN security protocols was WEP, which was labeled as inadequate and replaced by WPA, due to its many flaws and security shortcomings. WPA is also called as the draft of IEEE 802.11i standard. WPA uses TKIP for dynamic manipulation od encryption keys, and it uses algorithm RC4 for data encryption. Although WPA uses same encryption algorithm RC4 like WEP, better key manipulation and derivation is what makes it more robust than WEP. Full implementation of IEEE 802.11i standard was achieved with WPA 2, released later on. WPA 2 has separated encryption from authentication. It also has two different modes, Enterprise and Personal (PSK) and it provides excellent security solution for home and corporate WLAN networks. WPA 2 uses two methods based on the encryption standard AES for data protection and integrity. Those are CTR (Counter Mode) for encryption and CBC-MAC for data integrity. For data encapsulation and transfer it uses protocol CCMP. With WPA 2 all security flaws and vulnerabilities of its predecessors are addressed. Different types of attacks (attacks known as Chopchop, Bittau's fragmentation, FMS, PTW, Beck-Tews), which were used to distort wi-fi securities, are now impossible to use. Although brute force and dictionary attacks in theory can always lead to compromising network security, in practice, depending on the passphrase used, procedure can take for years, which makes them impractical. In order to achive that passphrase must be composed of uppercase, lowercase, numbers, symbols and it should contain at least 10 characters. All of this, the robust protection and resistance to all types of attacks, makes WPA 2 adequate security protocol for all wireless local area networks.