I'd guess because you didn't answer his question "where can I go learn about this?". You told him how to do it.

I'm curious, what's the difference between the two: being told how to do it, and being told where to go to be told how to do it?

If you go read a book like the one I recommended you'll be getting an education in the various sorts of ciphers out there and techniques to break them. The specific answer given above is how to break this particular cipher, thus it's not really far off giving the answer. The topic is more broad and interesting than that.

Step off the ledge, man. Downvotes happen.

Still, it's a common courtesy that if you downvote someone, you tell them why. I think most of us are here for hopefully enlightened discussions, driven by a yearning to learn, share, and explore various topics. We want to be taken seriously, for the most part, and take seriously what we say. Yes, at the end of the day it's just "internet points", but that's belittling our experiences and interactions here to be so dismissive to suggest one should just ignore them.

If that was the intended design, then perhaps votes should be hidden from users as well, so that we'd never know if we were voted up or down; but, I think the design is intended to somewhat subtly clue us in about whether our opinions and statements are popular, controversial, or whatever. It's a feedback loop, and most forms of conversation involve such indirect feedback loops in the form of non-verbal communication -- though in real-life, it's heavily augmented by body language, facial expressions, voice tone and inflection, etc. We don't have those luxuries here, and so the only non-verbals we're left with are the up-arrows.

It's one thing to receive a single down-vote, hell you can't please everyone, right? However, when you try in earnest to participate in a conversation, and you receive the equivalent of a "shut up" from the crowd, then you're left wondering: did I miss the entire point? Did I accidentally offend someone? Was I factually incorrect?

For a healthy conversational atmosphere, it helps to resolve these issues, so that we can improve our communication -- and hopefully avoid the need for any downvotes in the future.

I think being off work recovering from a minor op, and thus house-bound, is making me ratty. :(

It's just internet points, no worries. Everyone who matters can see you were trying to help. Hope you recover soon.

True, but on the receiving end a down vote feels like someone saying "No! You are Wrong!" and then offering nothing constructive.

Some days, I wish I could down vote down votes.

Sometimes downvotes are just fat-finger errors.

That is called upvoting.

No worries, best of luck with the convalescence!