Characterizing a Time–Memory Tradeoff Against PudgyTurtle

Abstract PudgyTurtle is not a cipher, but rather an alternative way to utilize the keystream in binary-additive stream-cipher cryptosystems. Instead of modulo-2 adding plaintext, uses encode 4-bit groups and then encipher each codeword. One goal make time–memory tradeoff attacks more difficult. Here, we investigate one such attack (a modification well-known Babbage–Golić method), show that its time-complexity harder on average than analogous against standard stream cipher; may approach ’brute-force’ attack; can be reduced by certain parameter choices; formulated terms probability distribution which amenable simulation.