#!/usr/bin/python3 '''This is the same as the previous, but it uses non-return to zero to encode the binary.''' import random lower = b'abcdefghijklmnopqrstuvwxyz' upper = lower.upper() plaintext = [b'The next one is in Morris Code. Unlike the previous two, ' b'they will actually need to determine some sort of key.', b'Morris code with a key? That sounds bizarre. probable cause'] def encode(text): out = bytearray() mask = 0x80 state = 0 for t in text: for i in range(8): next = t & mask if not state and not next: out.append(random.choice(upper)) out.append(random.choice(lower)) elif not state and next: out.append(random.choice(lower)) out.append(random.choice(upper)) elif state and not next: out.append(random.choice(upper)) out.append(random.choice(lower)) elif state and next: out.append(random.choice(lower)) out.append(random.choice(upper)) state = next t = t << 1 return bytes(out) def decode(text): out = bytearray() i = 0 while i < len(text): c = 0 mask = 0x80 for j in range(8): a = 0 if text[i] in lower else 1 b = 0 if text[i+1] in lower else 1 assert a != b, 'bad encoding' if b: c = c + mask mask = mask >> 1 i = i + 2 out.append(c) return bytes(out) c = encode(plaintext[0]) print('