Can/Which encryption algorithms be daisy chained to create a cryptographic computational puzzle? Goal

Create a computational puzzle that is fast to generate, takes an average computer minutes to solve, doesn't have any exploitable weaknesses, makes use of existing/tested encryption algorithms

Problem

Let's say we have a string: "Prefix: LLLLLLLLLLLLLLLLLLLLLL" where L can be any alphanumeric character, "Prefix: " is a pre-set prefix, and "LLLLLLLLLLLLLLLLLLLLLL" the solution to the puzzle.

Let's pick 3 encryption algorithms (as an example), AES256, Triplefish, Camellia

The puzzle-creator takes "Prefix: LLLLLLLLLLLLLLLLLLLLLL", encrypts it with AES256 using key_AES256, then Triplefish with key_Triplefish, then Camellia with key_Camellia, resulting in a daisy_chained_puzzle

To the puzzle-solver, the puzzle-creator sends daisy_chained_puzzle, key_AES256 with 1-character prefix missing, key_Triplefish with 1-character prefix missing, key_Camellia with 1-character prefix missing

The puzzle-solver exhaustively tries all combinations of those 3 missing characters, and returns the solution once it stumbles onto a decrypted solution with "Prefix: ", and deducts that the solution is the suffix "LLLLLLLLLLLLLLLLLLLLLL"

Worries

Would the provided "Prefix: " provide a weakness that can be exploited?

Would providing the suffix of each key result in a weakness?

Question

Can encryption algorithms be used daisy chained like this to create a simple computational puzzle / which encryption algorithms would be ideal for the task?
Can encryption algorithms be used daisy chained like this to create a simple computational puzzle…


It can be done, but remember encryption algos are built to be (among other things) fast/speedy while hash algos generally tend to be slower (which is the main reason why — as an example — Bitcoin uses SHA256d for its POW). This is one of a few reasons I would recommend to not use encryption algos for blockchain-alike Proof Of Work thingies.

Instead, I would recommend using hashes. An alternative would be hash based MACs (HMACs) as they allow to tweak things using a secret (what some call the password value) or maybe even things like Argon2 which allow further tweaking which (among other things) can influence speed (read: hardness to solve, while avoiding some of the main probs arising from potential ASIC and GPU implementations).


  …which encryption algorithms would be ideal for the task?


Depending on the length of your puzzle, it's going to be less a question of encryption algo, but more a question of algo type (stream cipher or block cipher) and (when using block ciphers) the mode of operation.

Last but not least, related to your


  …takes an average computer minutes to solve, …


you should be aware that computer systems differ greatly and recent CPUs even have AES functionality embedded which raises an even bigger problem when trying to balance out the several systems out there to make your puzzle fair.