They are not. “We only have a single keystream; we do not recover the keys used for encryption in generating the keystream,” Tews said.

To describe the attack succinctly, it’s a method of decrypting and arbitrarily and successfully re-encrypting and re-injecting short packets on networks that have devices using TKIP. That’s a very critical distinction; this is a serious attack, and the first real flaw in TKIP that’s been found and exploited. But it’s still a subset of a true key crack.

Arstechnica has a fantastic technical review on the subject.