57 lines
1.6 KiB
Python
Executable File
57 lines
1.6 KiB
Python
Executable File
#!/usr/bin/python3 -u
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import signal
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SQUARE_SIZE = 6
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def generate_square(alphabet):
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assert len(alphabet) == pow(SQUARE_SIZE, 2)
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matrix = []
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for i, letter in enumerate(alphabet):
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if i % SQUARE_SIZE == 0:
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row = []
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row.append(letter)
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if i % SQUARE_SIZE == (SQUARE_SIZE - 1):
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matrix.append(row)
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return matrix
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def get_index(letter, matrix):
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for row in range(SQUARE_SIZE):
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for col in range(SQUARE_SIZE):
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if matrix[row][col] == letter:
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return (row, col)
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print("letter not found in matrix.")
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exit()
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def encrypt_pair(pair, matrix):
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p1 = get_index(pair[0], matrix)
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p2 = get_index(pair[1], matrix)
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if p1[0] == p2[0]:
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return matrix[p1[0]][(p1[1] + 1) % SQUARE_SIZE] + matrix[p2[0]][(p2[1] + 1) % SQUARE_SIZE]
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elif p1[1] == p2[1]:
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return matrix[(p1[0] + 1) % SQUARE_SIZE][p1[1]] + matrix[(p2[0] + 1) % SQUARE_SIZE][p2[1]]
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else:
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return matrix[p1[0]][p2[1]] + matrix[p2[0]][p1[1]]
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def encrypt_string(s, matrix):
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result = ""
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if len(s) % 2 == 0:
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plain = s
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else:
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plain = s + "lsi28c14ot0vbf7nagh3mpjuxy5kwz6edqr9"[0]
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for i in range(0, len(plain), 2):
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result += encrypt_pair(plain[i:i + 2], matrix)
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return result
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alphabet = open("key").read().rstrip()
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m = generate_square(alphabet)
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msg = open("msg").read().rstrip()
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enc_msg = encrypt_string(msg, m)
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print("Here is the alphabet: {}\nHere is the encrypted message: {}".format(alphabet, enc_msg))
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signal.alarm(18)
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resp = input("What is the plaintext message? ").rstrip()
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if resp and resp == msg:
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print("Congratulations! Here's the flag: {}".format(open("flag").read()))
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# https://en.wikipedia.org/wiki/Playfair_cipher
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