Decode this…
guvf zrffntr unf orra rapbqrq hfvat gur fvzcyr vqrn bs cynpvat gur yrggref bs gur nycunorg ebhaq n qehz naq ebgngvat rnpu yrggre 13 cynprf, fb n orpbzrf z. v’yy or hfvat vg gbzbeebj jvgu fghqragf nf n fvzcyr rkrepvfr. gur fghqragf jvyy unir gb jbex va cnvef hfr n gnoyr bs crepragntr serdhrapvrf bs gur yrggref [...]
guvf zrffntr unf orra rapbqrq hfvat gur fvzcyr vqrn bs cynpvat gur yrggref bs gur nycunorg ebhaq n qehz naq ebgngvat rnpu yrggre 13 cynprf, fb n orpbzrf z. v’yy or hfvat vg gbzbeebj jvgu fghqragf nf n fvzcyr rkrepvfr. gur fghqragf jvyy unir gb
- jbex va cnvef
- hfr n gnoyr bs crepragntr serdhrapvrf bs gur yrggref va gur nycunorg naq n ovg bs pbzzba frafr gb qrpbqr gur zrffntr
- rapbqr n zrffntr naq fraq vg gb nabgure cnve guvf vf cercnengvba sbe fbzr jbex ba gur cflpubybtl bs pbzchgre unpxref.
Did it work?
18th Oct: Well, the codebreaking activity went down quite well – the students were determined to solve the rather simpler rot13 message given. They had a table of the frequencies of letters in English words. I used this as an introduction to the hacker mind and why hackers use online communities so much. The logic was as follows…
- Work in pairs
- Try to find as many letters/words as you can (Scrabble?)
- (after 5 min) Share your information with other pairs
- Work as a class group of pairs to solve the problem
- Can you find a rule for the ‘substitution code’ being applied?
- How many bytes of information would it take to send someone details of the substitution rule? Less than a table of 26 letters and 26 coded letters (ie less than 52 bytes plus spaces)?
The feedback went along the lines of…
- How did you feel working on the puzzle?
- How did sharing the information from other pairs help?
Results with a mature day group were interesting: two of the pairs got a long way to solving the puzzle – they had about 10 words sorted – using frequency analysis and guesswork from the shape of the words.
When we pooled the information from the pairs, the combined result was much better and one member of a pair that had ‘switched off’ became re-engaged and spotted the rule (move letters 13 along)
The moral is obvious – Cognitive puzzle solving is hard but hackers can multiply their efforts by using online communities.
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bodmas.org, 17 October 2004