[Home]WirelessEthernet

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A wireless networking protocol, based on ethernet but not strictly ethernet, that is becoming a popular way of keeping LapTop?s, and thus their users, from being tied down by wires. The standard is IEEE 802.11, with 802.11b being an enhancement pushing it to 11MBps. It is also being developed for HandHeld computers.

Security

From CompRisks Digest 21.55:

WEP is the security protocol used in the widely deployed IEEE 802.11 wireless LAN's. This protocol received a lot of attention this year (2001), and several groups of researchers have described a number of ways to bypass its security.

Attached you will find a new paper which describes a truly practical direct attack on WEP's cryptography. It is an extremely powerful attack which can be applied even when WEP's RC4 stream cipher uses a 2048 bit secret key (its maximal size) and 128 bit IV modifiers (as proposed in WEP2). The attacker can be a completely passive eavesdropper (i.e., he does not have to inject packets, monitor responses, or use accomplices) and thus his existence is essentially undetectable. It is a pure known-ciphertext attack (i.e., the attacker need not know or choose their corresponding plaintexts). After scanning several hundred thousand packets, the attacker can completely recover the secret key and thus decrypt all the ciphertexts. The running time of the attack grows linearly instead of exponentially with the key size, and thus it is negligible even for 2048 bit keys.


Here in Switzerland we have many antennas for mobile phones. People complain about the electric fields and about the ugly sights. This is why the putting up of antennas is getting heavily regulated. I wonder what will happen ones the wireless wave hits such areas -- more antennas, more traffic, more people complaining about chronic pain and bad sleep? Wether such fears are justified or not, I wonder how yet-another-wireless infrastructure will be built. -- AlexSchroeder

The sensible thing would be for both systems to use the same antennas, and indeed, the same network. But when has technological innovation ever been sensible when driven by commerce...? -- Tarquin

An even more sensible thing would be for every laptop to send not only its own packets, but also forward packets from other laptops further away from the wired access point. Counter-intuitively, sending these "extra" packets takes less battery power (with typical conditions). With this sort of system, as the laptop/handheld density increases, the access points only talk to the nearest few laptops/handhelds, which grow closer and closer, requiring smaller and easier-to-hide access point antennas (even though you need more access points). Eventually the antennas of each access point grow small enough that they can hide behind the curtains of second-story windows, becoming invisible. -- DavidCary

Is this a MeshNetwork?? -- SunirShah

Yes. I see other wiki discussing similar ideas -- [the wireless sensor network wiki], [the open source mesh wiki]. -- DavidCary

David... Is there a bit of an explanation regarding why less battery power is needed? This is, after all, "counter-intuitive". -- HansWobbe


I have been working with iPaq HandHelds and 802.11b, and it has been working very nicely. The one thing I've been having problems with is that it takes a PCMCIA jacket, and the jacket has its owm battery to feed the ethernet card, and if the battery slips below around 50% battery life, you suddenly lose connection. Another problem for PervasiveComputing, I guess. -- anon.


CategoryPervasiveComputing

Discussion

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