I think some of the questions obviously vary in applicability dependent upon the role being interviewed but in general most of the questions I would say form a good set of base questions to sort the wheat from the chaff.
Going through them I see that I got a few wrong, most notably with elements of crypto, so it's helpful in terms of me understanding the areas I'd need to improve, which for me would be the best thing I could take away from an interview where I'm not offered the job I want.
"Cryptographically speaking, what is the main method of building a shared secret over a public medium?"
I overlooked diffie-hellman, expecting something more complex and goofed out. My answer was "I wouldn't use a public medium, I'd go out of band to share the secret".
Having said that, I understand that crypto is not my area, and that I need to improve, which gives me some good pointers moving forward. Theoretical crypto isn't my thing (infrastructure, malware reversing and other bits of app sec are my thing for want of a better term - as far as crypto goes there are other people in the team that do a better job than me and I accept I'm lazy in this respect so it's a good pointer for me to improve).
Don't worry, it's common to get poorly worded questions wrong when you don't understand what exactly the examiner is asking. In this case, I too would have gotten wrong unless you replaced "building" with "exchanging".
Going through them I see that I got a few wrong, most notably with elements of crypto, so it's helpful in terms of me understanding the areas I'd need to improve, which for me would be the best thing I could take away from an interview where I'm not offered the job I want.