I'm thinking the encoding scheme should maybe include big/small as the fifth bit in each flame, maybe inside/outside for the 6th bit. This would give you 2^6 or 64 possible bit-strings for each flame, usable as a base64 alphabet for a Bacon cypher. There needs to be a number of flames related to the number of chars in a private key format, or a decoded string that would represent a clue in readable text, and the latter may be very tough to detect with any sort of cracking algo.
Several people mentioned it, but it often gets forgotten here: The money is in the
1FLAMEN6rq2BqMnkUmsJBqCGWdwgVKcegd address. That "FLAME" at the beginning certainly is not random, which means that it is generated using some vanity address generator, which again means that the private key which corresponds to this address is totally random, completely uncontrollable by the creator of the puzzle. There's 0 chance some meaningfully, readable text or something like that is brainwallet which is needed to solve the puzzle, there is no brainwallet and the solution we are looking for is either:
- private key in WIF format, or some other encoding like QR code
- some specific number that obviously pops out and is used as secret exponent
That's what makes this much harder, we are not looking for a string, we are looking for a (random) number.