The IV is static: Reuse of the same IV produces identical key streams for the protection of data, and because the IV is short, it guarantees that those streams will repeat after a short time. The 24-bit string used to initialize the key stream generated by the RC4 algorithm, is a relatively small field when used for cryptographic purposes. In Shared Key Authentication, the WEP key is used for authentication in a four step challenge-response handshake.ĥ Open System & Shared Key AuthenticationĦ What’s wrong with WEP? The IV is too small and in clear text: It’s a 24-bit field sent in the clear text portion of a message. At this point, the client must have the correct keys. Subsequently WEP keys can be used for encrypting data frames. Any client can authenticate with the Access Point and then attempt to associate. In Open System Authentication, the WLAN client need not provide its credential to the Access Point during Authentication. 128-bit WEP uses 104-bit key, which is also concatenated to a 24-bit Initialization Vector.Ĥ WEP Authentication Two Methods of Authentication: Open System Authentication and Shared Key Authentication. It is used to prevent a sequence of text that is identical to a previous sequence from producing the same exact cipher-text when encrypted. (IV): A continuously changing number used in combination with a secret key to encrypt data.
Standard 64-bit WEP uses a 40-bit key, which is concatenated with a 24-bit Initialization Vector (IV) to form the RC4 key. Each byte of data will be encrypted using a different packet key. WEP has been demonstrated to have numerous flaws and has been deprecated in favor of newer standards such as WPA and WPA2.ģ How does WEP work? WEP uses RC4 algorithm to encrypt the packets of information. Its intention was to provide data confidentiality comparable to that of a traditional wired network. WEP is a weak security algorithm for IEEE wireless networks.
WPA was designed as an interim software solution for WEP it runs on the same hardware that WEP does.Presentation on theme: "Wireless Protocols WEP, WPA & WPA2."- Presentation transcript:Ģ What is WEP? Wired Equivalent Privacy (WEP) was included as the privacy component of the original IEEE standard ratified in September 1999. To add support for WPA or WPA2, some old Wi-Fi access points might need to be replaced or have their firmware upgraded. The recommended solution to WEP security problems is to switch to WPA2 or the less resource intensive WPA. The flaws discussed in this video include, It also talks about the flaws in general and gives the overview of the tools available on the new which can help in cracking the WEP key. This video talks about the remaining flaws with WEP as a protocol. Tutorial #2 talks about the flaws in the WEP protocol and explains few very important flaws. The WEP tutorial #1 covers the basic working of WEP protocol.
An additional 4 byte Integrity Check Value (ICV) is computed on the original packet using the CRC-32 checksum algorithm and appended to the end. The IV is sent in the clear with each packet. The IV is chosen by the sender and should be changed so that every packet won't be encrypted with the same cipher stream. The encrypted packet is generated with a bitwise exclusive OR (XOR) of the original packet and the RC4 stream. This key is composed of a 24 bit initialization vector (IV) and a 40 bit WEP key.
When WEP is active in a wireless LAN, each 802.11 packet is encrypted separately with an RC4 cipher stream generated by a 64 bit RC4 key. Those vulnerabilities were so strong that IEEE had to deprecate the WEP standard. But starting early 2001, many serious cryptographic vulnerabilities were discovered with WEP protocol. WEP was intended to provide the required confidentiality. Being broadcast medium wireless medium is highly susceptible to eavesdropping. Description: WEP (Wired Equivalent Privacy) is the only encryption standard supported in IEEE 802.11-1999 (commonly known as Wi Fi) standard.