Combining transposition and block substitution defeats simple cryptanalysis by first scrambling the letter positions and then applying different substitution keys to the resulting blocks. This ensures that guessing a single key yields completely unreadable gibberish, as the original word boundaries and letter frequencies are hidden.
Conditions: The method applies a transposition cipher first.; The method applies a block substitution cipher second.; The attacker attempts to decrypt using only one of the keys.
Combining transposition and block substitution defeats simple cryptanalysis by first scrambling the letter positions and then applying different substitution keys to the resulting blocks. This ensures that guessing a single key yields completely unreadable gibberish, as the original word boundaries and letter frequencies are hidden.
Conditions: The method applies a transposition cipher first.; The method applies a block substitution cipher second.; The attacker attempts to decrypt using only one of the keys.