Lab 14: ️ Enigma Machine - Simulasi Cipher Mesin Nazi Jerman

cd ~ && mkdir crypto-lab14 && cd crypto-lab14

python3 << 'PYEOF'
import string

class EnigmaSim:
    def __init__(self, rotor1, rotor2, rotor3, reflector):
        self.rotors = [rotor1, rotor2, rotor3]
        self.reflector = reflector
        self.positions = [0, 0, 0]
    
    def encrypt_char(self, c):
        if c not in string.ascii_uppercase:
            return c
        
        # Forward through rotors
        idx = ord(c) - 65
        for i in range(3):
            idx = (ord(self.rotors[i][(idx + self.positions[i]) % 26]) - 65 - self.positions[i]) % 26
        
        # Reflector
        idx = ord(self.reflector[idx]) - 65
        
        # Backward through rotors
        for i in range(2, -1, -1):
            rotor_pos = (ord(self.rotors[i][idx]) - 65)
            idx = (rotor_pos - self.positions[i]) % 26
            idx = (idx + self.positions[i]) % 26
        
        # Rotate rotors
        self.positions[0] = (self.positions[0] + 1) % 26
        if self.positions[0] == 0:
            self.positions[1] = (self.positions[1] + 1) % 26
            if self.positions[1] == 0:
                self.positions[2] = (self.positions[2] + 1) % 26
        
        return chr(idx + 65)

# Rotor wirings (simplified)
rotor_I = "EKMFLGDQVZNTOWYHXUSPAIBRCJ"
rotor_II = "AJDKSIRUXBLHWTMCQGZNPYFVOE"
rotor_III = "BDFHJLCPRTXVZNYEIWGAKMUSQO"
reflector_B = "YRUHQSLDPXNGOKMIEBFZCWVJAT"

enigma = EnigmaSim(rotor_I, rotor_II, rotor_III, reflector_B)

plain = "HELLOENIGMA"
cipher = ''.join(enigma.encrypt_char(c) for c in plain)

# Reset for decryption
enigma2 = EnigmaSim(rotor_I, rotor_II, rotor_III, reflector_B)
decrypted = ''.join(enigma2.encrypt_char(c) for c in cipher)

print(f"Plain:    {plain}")
print(f"Cipher:   {cipher}")
print(f"Decrypt:  {decrypted}")
print()

# Demonstrasi: huruf yang sama → cipher berbeda
enigma3 = EnigmaSim(rotor_I, rotor_II, rotor_III, reflector_B)
for i, c in enumerate("AAA"):
    result = enigma3.encrypt_char(c)
    print(f"  'A' ke-{i+1} → '{result}' (rotor bergerak!)")
PYEOF