CSE 588 - Spring 2002 - Transcription

University of Washington Department of Computer Science & Engineering

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WEP (Wireless Equivalent Privacy) is based on RC4 - which uses a vector and a key.
RC4 goals is to ensure integrity, privacy and access control.
However, it has some security flaws.
If you know the XOR of the two original messages and you use a straight plain text attack, you could potentially determine the vector used.
RC4 is also vulnerable to packet replay attacks that's why usually wireless networks are run on top of a VPN.
Multicast
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Why?
Needed for:
- efficiency
- rendez vous cases (when the sender and the receiver don't know each other)
How to implement it?
Basically 3 solutions:
a) IP router level
b) Overlay (e.g. Content Delivery Network)
c) Application level
a) has an efficiency advantage
b) & c) have a flexibility, simplicity and ease of deployment advanatge
All routers support multicast on the internet yet almost none have it enabled. Why?
- Inefficiency of the Broadcast and Prone design
- No applications are requiring it
- Economic intensive
So why do routers support it in the first place? mainly because of the fear of loosing customers who would require it in the future.
IP Routing Multicast Service Model:
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Delivery model: Best effort
Addressing: using group addresses
Multiple sender or single sender?
- Depends on economic incentive
- Single source allows access control
- Single source is simpler on the router level
How does the receiver join the group address? explicitly or implicitly?
PIM (protocol independent multicast) is a sample implementation of explicit join.
PIM uses hop-by-hop joins
Overlay Routing Multicast Service Model:
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Second half...

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