1. WEP & WPA
Mandy Kershishnik

2. Define for me.. . WEP- Wired Equivalent Privacy
method to secure IEEE wireless networks
part of the IEEE wireless networking standard
IEEE set of standards for wireless local area network (WLAN) computer communication, developed by the IEEE LAN/MAN Standards Committee

3. Define for me.. . WPA- Wi-Fi Protected Access
class of systems to secure wireless (Wi-Fi) computer networks
created in response to several serious weaknesses researchers had found in the previous system, Wired Equivalent Privacy (WEP)

4. Overview.. .
WEP in depth
WPA in depth
IUP’s summer issue
Conclusion

5. WEP.. . provide confidentiality comparable to wired network
Cryptanalysis unveiled several weaknesses
WEP -> WPA in 2003
WEP -> WPA2 in 2004
ALL not lost.. .
provides a level of security that may deter casual snooping

6. WEP.. . 128-bit WEP key Confidentiality: RC4
Integrity: CRC-32 checksum
128-bit WEP key
26 Hex characters
(0-9 and A-F)
1 char = 4 bits
(so… 4 * 26 = 104 bits)
24-bit IV (initialization vector)

7. Authentication (2 methods)
WEP.. .
Authentication (2 methods)
1) Open System
WLAN client doesn’t have to provide credentials to “access point” during authentication
Essentially, any client (regardless of key) can authenticate with the “access point” THEN attempt to associate
No authentication actually occurs
After authentication & association, WEP used for encryption of data frames (as long as client has correct keys)

8. WEP.. . 2) Shared Key Four-way challenge-response handshake
1) client station sends authentication request to “access point”
2) “access point” sends back clear-text challenge
3) client encrypts challenge text using the configured WEP key; sends it back in another AUTH request
4) “access point” decrypts material; compares it with clear-text sent; depending on success of comparison, the “access point” sends back a positive or negative response
After the authentication and association, WEP can be used for encrypting the data frames

9. WEP.. . Security Flaws Short IVs & keys Static keys
Keystreams that are too similar
Decryption of frames
Static keys
doesn't provide function that supports the exchange of keys among stations
admins and users generally use the same keys for log periods of time
Cyclic Redundancy Check (CRC) insecure
is possible to alter the payload and update the message CRC without knowing WEP key

10. WPA.. . Created by Wi-Fi Alliance
designed to work with all wireless NIC cards
must be enabled and chosen in preference to WEP
WEP is usually presented as the first security choice in most installation instructions
“personal mode” passphrase often too short (6-8 chars)

11. WPA.. .
2 modes
1) designed for use with an IEEE 802.1X authentication server
Encrypted RC4 stream cipher
128-bit key
48-bit IV (initialization vector)
Temporal Key Integrity Protocol (TKIP)
Dynamically changes keys as system used
Defeats key recovery attacks on WEP
Message Integrity Code (MIC)
Algorithm- Michael
Frame counter
Prevents replay attacks

12. WPA.. . 2) Pre-shared key (PSK) mode
designed for home and small office networks
Passphrase
printable ASCII characters OR 64 HEX digits (256 bits)
may be stored on user’s computer (avoid re-entry)
Stored in Wi-Fi “access point”
* strong passwords are crucial
* some methods to bypass weak passphrases
Software / hardware interface that adds Wi-Fi adapter or appliance to network
Short challenge phrases

13. IUP & WEP / WPA.. . DUAL Broadcasting WPA- IUP network (TKIP)
Visible
WEP- AuthorizedUseOnly network
Invisible

14. Conclusion.. .
WEP in depth
WPA in depth
Security issues
Application

15. Resources.. .