Software Testing

What I learned from my puzzle exercise

I’d like to say thank you to everyone who participated in this little puzzle exercise and most especially to everyone who provided feedback. I hope you had fun with it. Well done again to Rushmila Islam who was the first to work out the puzzle.

I have posted .the solution at the bottom of this post. YOU HAVE BEEN WARNED.

I learned a lot more than I thought I was going to. Firstly and probably the most obviously, I learned a lot about cryptography that I didn’t previously know. Thanks to James Bach for the collection of links.
Braingle was probably the best of the bunch. Thanks also for the link to Sebi’s puzzle.

I found Jürgen Plasser‘s answer fascinating. I hadn’t encountered measuring entropy of text as a way to inform possible encryption techniques. It’s something I’d like to look into further.

It was interesting to see how close people got with their responses. Many people had several correct pieces of the puzzle, but not quite enough to solve it completely.

I think most people gave me way too much credit for the amount of crypto knowledge I’d have had as a high-school student. I didn’t have access to teh intarwebs back then, and time that I could have spent in the library was more likely to be spent playing role-playing games or painting miniatures or similar valuable life skills.

One of the things that this puzzle made abundantly clear to me was the value of information before and after it becomes known. Without the key information, it was a real puzzle. Far more so than I had originally anticipated. Having all the information at hand, the puzzle seems obvious and simple in hindsight.

It drove home for me just how difficult it is to convey the value of a tester to those who don’t understand what good testers do. Even the distinction that testers are a source of information (so is a book. so what?) doesn’t necessarily convey the effort that is involved at producing this information.

Some people went to a great deal of effort; tried some very cool things. That was the most gratifying thing for me. The answer was ultimately irrelevant. I got to see how you guys think. As testers, we are often showing others the fruits of our effort, but not the beauty of the effort itself. Having been able to do that here, at least in part, I think is pretty cool. Thank you again to everyone who shared.

SPOILER ALERT – Explanation of the cipher follows.

The message was encoded with direct character substitution with a few added extras. The message reads top-down, right to left. The first two characters provide the character offset – character 1 – character 2 = offset.

The spaces themselves mean nothing, but exist primarily for obfuscation though I did put them in diagonally in the first puzzle to give a clue to the direction of the word flow. Spaces in the actual message are represented by vowels, so in this sense, vowels do double duty in that they can represent their offset character or a space.

5 thoughts on “What I learned from my puzzle exercise

  1. Your hints were terrible. They were exactly like not getting hints, which was what I was doing before I looked at the hints. I think your dream of becoming a professional hinter is at risk.

    Otherwise, I had a lot of fun with this puzzle. I spent a lot of time analyzing the potential affect of the spaces. I also worked the puzzle from all directions, including the one you identified at the right one. I’m not yet sure why my methods didn’t uncover the solution, so I need to look at that more carefully.

    — James

  2. Heh.
    I was trying to strike a balance between giving too much information away and providing something that was useful. I knew the cipher was kinda fragile, and being too obvious with a hint such as ‘how many letters are there in the code if you remove all the spaces?’ would have given the game away. Something I’ll keep in mind for any future puzzles, I guess. I appreciate the feedback.

    Glad you had fun with it.

  3. Nice puzzle mate, reminds me of the ciphers I used to add to deployment emails 🙂

    > As testers, we are often showing others the fruits of our effort, but not the beauty of the effort itself.

    Well said. Although my job description does’t have even have the word “test” in it, the things I have learnt as an exploratory tester makes me more confident in communicating the effort undertaken to develop my (hopefully) elegant solutions.

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