Analiza sigurnosnog protokola WPA2 u bežičnim lokalnim mrežama

undergraduate thesis

• Title (english): Analysis of WPA2 security protocol in wireless local area networks
• Author: Toni Smoljo
• Mentor: Željko Ilić (mentor)
• Committee member: Željko Ilić (predsjednik povjerenstva)
• Committee member: Nenad Markuš (član povjerenstva)
• Committee member: Matija Šulc (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2016-07-11, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering

Abstract

Za razliku od ožičenih mreža, signal kod bežičnih mreža slobodno se širi zrakom. Da bi sadržaj odašiljanih informaciju zadržao privatnost i cjelovitost, potreban je što bolji sigurnosni protokol zaštite. Protokol WEP, zbog nedostataka u algoritmima i funkcijama zaštite podataka, proglašen je nepouzdanim, te zamijenjen boljim zaštitnim protokolom WPA. Iako bolji od protokola WEP, WPA je bio požureni „predložak“ (djelomično je zadovoljavao metode propisane standardom IEEE 802.11i) načina zaštite predviđenim standardom IEEE 802.11i. Koristi protokol TKIP za manipulaciju ključevima, što čini zaštitu robusnijom od zaštite koju pruža protokol WEP. Za enkripciju podataka koristi algoritam RC4, kojega je koristio i protokol WEP. Potpuna implementacija standarda IEEE 802.11i postignuta je sa sigurnosnim protokolom WPA 2. S odvojenom enkripcijom podataka i autentifikacijom, te s dvije izvedbe Enterprise i Personal (PSK), protokol WPA 2 pruža odličnu zaštitu osobnih i korporacijskih bežičnih lokalnih mreža. Za enkripciju podataka protokol WPA 2, oslanja se na metode zasnovane na enkripcijskom standardu AES. Dvije metode pomoću kojih se postiže zaštita i cjelovitost podataka su CTR (zaštita) i CBC-MAC (cjelovitost). Za enkapsulaciju i prijenos se koristi protokol CCMP. Protokol WPA 2 je uspješno otklonio sve nedostatke i ranjivosti svoja dva prethodnika. Razni napadi (kao što su „Chopchop“, „Bittau's fragmentation“, „FMS“, „PTW“, „Beck-Tews“), pomoću kojih su se narušavale sigurnosti bežičnih lokalnih mreža, sada su potpuno neizvedivi. Napadi Brute force i napadi metodom rječnika teorijski uvijek mogu probiti sigurnosni protokol WPA 2. U praksi, ako se koristi lozinka s dovoljnim brojem i random znakovima, taj postupak može trajati godinama. Upravo ta robusnost zaštite protiv različitih vrsta napada čini protokol WPA 2 adekvatnim za zaštitu bežičnih lokalnih mreža.

Abstract (english)

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.

• Keywords: WLAN; protokol WPA2; sigurnost WLAN
• Keywords (english): WLAN; WPA2; AES; CCMP; CTR; CBC-MAC
• Language: croatian
• URN:NBN: urn:nbn:hr:168:142322
• Study programme: Title: Computing; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka računarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka računarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2018-02-06 11:50:35