Re: Seriation

On Sat, 1 Feb 2025 11:00:19 +0000, Richard Heathfield wrote:

But yes, being easy (but not /quite/ trivial) to crack was indeed at the
heart of SCOS.

Welcome back. I very much enjoyed the challenges that you and a few others
provided in the past. I've spent a bit of time working through the
National Cipher Challenges and I'm now following the Alan Turing
Cryptography Competition and Mathsbombe. I'm definitely not an cipher
expert, but it is fun and I can see it's a skill that takes time and
effort to develop.

I'm quite old and have a lot of interests, so sometimes I don't follow
everything as closely as I would like. That was the case with SCOS.

I did have a bit of trouble with SCOS, not because it was hard to decrypt,
but my implementation wasn't... There's a word, but I'm not sure what it
is... When you perform an operation on a set, the result of that operation
is should be guaranteed to belong to the same original set, but in my case
it wasn't. So in this case, when encrypting and decrypting occasionally,
due to some odd punctuation mark, or an accented character, the result
would lie outside the reasonable bounds of characters. The web, which I
often use as a source of plain text, is full of such characters. That was
my problem, not a problem with SCOS, but it did cause me some grief.

Best wishes, good to have you back.

--
David Entwistle