Biometrics?
What are the possibilities for widespread, and reliable, biometrics?
Whipping out a smartphone or keyfob every 5 minutes is indeed a pain. Whipping out an eyeball every five minutes, less so. Really need to rephrase that last sentence.
Also, thanks for scaring the bejesus out of me re OSI layers. I've been preaching a mere 7 of the buggers all this time.