01-19-2023, 05:40 PM
first, without "really" knowing how coinbase stores or computes the seedphrase, it is impossible to attack this encryypted string
you assume storing the frst letters, why so complicated? lets assume the follwing, bip 39 is standardized 2048 words in a sorted manner, so all you need to store is the position of the words in that dictionary, for storing max 2048 in hex you need 3 chars., 12 * 3 = only 36 chars needed with plain position in dict to hex
but the next way for storing could be a vector like approach, instead of storing the exact postion per word, the ongoing position is computed by index predecessor + value X = index word+1 and so on, so you dont store the index itself but just the positional difference
there are more ways but anyway, i dont think you can attack this unless you know how coinbase computes the input for the encryption (known plaintext attack)
you assume storing the frst letters, why so complicated? lets assume the follwing, bip 39 is standardized 2048 words in a sorted manner, so all you need to store is the position of the words in that dictionary, for storing max 2048 in hex you need 3 chars., 12 * 3 = only 36 chars needed with plain position in dict to hex
but the next way for storing could be a vector like approach, instead of storing the exact postion per word, the ongoing position is computed by index predecessor + value X = index word+1 and so on, so you dont store the index itself but just the positional difference
there are more ways but anyway, i dont think you can attack this unless you know how coinbase computes the input for the encryption (known plaintext attack)