In my opinion, an acceptable password length should be L in ln(alphabetSize^L)/ln(2) = (B bits of entropy). For a Bech32 character set (since it excludes ambiguous characters), alphabetSize = 32. A good password should have been 96 and 256 bits of entropy, with 128 bits being my personal preference. This means L = (B)*ln(2)/ln(alphabetSize) = 128*ln(2)/ln(32) =