The good news is that you are on the right track, the better news is that the rule is indeed simple.
Yes, you correctly understood that each index letter corresponds to the four optional substitutions around it, which is the way to counteract the frequency analysis, I use a 1-to-2 substitution table in password management, which has been calculated to prove validity, and I hope this 1-to-4 works better.
Here's a new tip:
Recovering a seed phrase requires information not only about the seed word itself, but also about the order of the words. Usually we write down the words in order, so we ignore the important information about the "
position" of the words. If you encode the word's sequential number with the word, then each word and its sequential number form a "
block" that can be placed out of order, which is a very important way to write seed phrases in secret.
I say the rule is simple because it uses one or two "
blocks" of information about how to choose the cards (even the black ones need to be chosen because I may have several different sets of cards for myself, for different purposes, and sometimes they tend to get mixed up with each other), how to place them, and how to rotate the 4 substitution tables. Based on this information, 11 of the 12 combinations given can just be left alone and the correct one used to decode the remaining information.
No, in fact, these letters contain more information, and as we all know, to record the BIP39 seed phrases, it's enough to record the first 4 letters of each seed word, so we have room to cram in more information that is necessary to perform substitution encryption.
Not entirely sure what you mean in here. Yes, it is enough if we have the first four letters of a word, because they are unique. So, we have more room to introduce information that will obscure these letters? For example, could URU/Yw be "aren" followed by another input that is used in your rule to help us go figure out the next word?
I've been looking at it since yesterday, but it's a loss of time until this point. We know absolutely nothing about your rule. It could be anything, like take the first cipher-letter ('U') and use it to find potential letters that it points given a combination using the silver and black cards (e.g., from the first of the twelve combinations, it points to 'h', 'j', 'n' and 'm'). That's just one of the nearly infinite rules I can think of.
I checked an account under the nostr post you shared, from BitCat, which I presumes is yours, because they're describing a very similar patent of securing passwords. As far as I can tell, it's infeasible to achieve reversal; our only hope is that you've used a "simple" rule, which could be utterly subjective.