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Only 10 people have ever solved this challenge (9 if you don't count bok, who created it), so its difficulty has got to be really high.

Looking at the pictures, one obvious approach would be to interpret them as ones and zeros, and then go from there. However, that would mean there are 251 bits of information here, which is an odd number in that it is not evenly divisible into bytes or nibbles. It is even a prime number.

I wonder what the "Cereal" is supposed to mean?

AMindForeverVoyaging wrote:Looking at the pictures, one obvious approach would be to interpret them as ones and zeros, and then go from there.

The alt text of the images suggests this, too.

I wonder what the "Cereal" is supposed to mean?

It is a hint, but in my opinion you can only understand it, if you know the solution.

Tron wrote: It is a hint, but in my opinion you can only understand it, if you know the solution.

Great, that's gonna help a lot then.

Any hints here? I'm really stuck.

Yeah, me too. Stuck ever since.

Cereal => Serial
I even had a look in the RS-232 Spec. though this is in the 'crypto' Section. Nothing found out yet...

Perhaps C-Real -> Floating Point -> Arithmetic Coding. But also -> Dead End...

You won't believe it - i also started with the RS232 specs (because of the homophone of Cereal and Serial) and in the end it helped. Ok, you don't have to take the specs too precise, i played a lot with different settings (Start-Stop-Parity-Bits), but as i said, with all these attempts in the end i got the solution.
The bad thing is: The solution has nothing to do with the Serial Communication, but this you'll find out once you got it

cyberwoozle wrote:Ok, you don't have to take the specs too precise, i played a lot with different settings (Start-Stop-Parity-Bits), but as i said, with all these attempts in the end i got the solution

Still beats me how you would end up with a prime number like that.

It's more than three years ago that i solved this one, therefore i don't remember exactly what i did and how i did it, but there's one thing for sure, i never thought about or met any prime numbers in my attempts.

On a physical RS-232-Line there can be 1, 1.5 or 2 Stop-Bits

Whereby 1.5 doesn't make sense ....

Well no matter how many start-/stop-/parity bits you use for a data transmission, unless the transmission is incomplete you will have as the number of data given a multiple of an integer number, which can never be a prime.

On the other hand, there have been challenges with incomplete data - two or three of the "Didactic" ones, if I remember correctly. So maybe it is not actually intended that the number of bits given here is prime. Or it might be a red herring.

According to the suns and clouds are shown in the challenge, the answer maybe has something to do with the Cloud API from Sun Microsystems. There are resources defining interfaces and protocols. But how to apply the lopsided number of 251 bits? By the way, this approach has nothing to do in the CRYPTO section...

Then it is the wrong approach Looking at history, the cloud API comes much later than the cipher used in this challenge. It's a very unusual cipher, so pencil and paper and observation is the best approach to start attacking it.

Is this task about serial line on-wire (physical signal) encoding?
If it is, does it contain transmission errors?