I am going through Dan Boneh's Cyprography lectures on Coursera.
In Lecture 6 https://class.coursera.org/crypto-010/lecture/6
At 7:30 minutes, he discusses the problems with 802.11b design. I understand his critique. However, he then moves on to what would be better design at 12:55 minutes.
He says that they could use a PRG to generate a very long key from the key and then use segments of the PRG(K) to encrypt each frame.
Even if you generate a very long PRG(K), considering the amount of traffic exchanged, wouldn't key still get repeated every few hours or so - i.e. you come to the end of the PRG(K), you have to start reusing first segment of PRG(K) again - which will lead to the key reuse problem. So what am I missing here?