Spitballing: could you make an encryption system based on 'unique hash functions'? A 'key generator' would create a transformation sequence from ciphertext to plaintext (using bit operations), then create a *reverse* transformation that can be encoded as a set of instructions but that doesn't reveal the original transformation sequence (and reversing the instructions won't reveal anything - i.e. the instructions are

equivalent to a custom hash function). Think of it like backdooring custom hash functions.

Then for rerandomization, something like chaining/merging sequences in a way that hides the base sequence...