Hey, thanks for writing! :) It must have been really hard to stick with the interview to the end.

I think your point at the end is of great importance. As a candidate, I assume the organization had assigned one or two of its most qualified people to be the face of the company. As much as they’re there to vet me, they’re there to “sell” the company and make sure quality candidates know everything there is to know so they are excited about working there. If that’s how a senior developer responds to your being wrong (at least in their mind — I am not getting into the concrete topic as I am hardly an encryption expert), it doesn’t sound like a place where you can make mistakes, learn from them, and grow.

It’s quite possible to nail an interview even if you make mistakes; it’s not just about what you say, it’s also how you say it, how you take criticism, how coachable you are.

But all that is true for the interviewer as well — a job interview is a two-way process and if you’ve had such a bad experience interviewing with this person, imagine what it would be like to work with them every day!

It's possible to express a different opinion or share something from your experience that stands in contradiction to what the interviewer states, or at least it should be. In my opinion, you did just fine, and you should be thankful for that advance warning you got :)