Python/ciphers/porta_cipher.py

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alphabet = {
"A": ("ABCDEFGHIJKLM", "NOPQRSTUVWXYZ"),
"B": ("ABCDEFGHIJKLM", "NOPQRSTUVWXYZ"),
"C": ("ABCDEFGHIJKLM", "ZNOPQRSTUVWXY"),
"D": ("ABCDEFGHIJKLM", "ZNOPQRSTUVWXY"),
"E": ("ABCDEFGHIJKLM", "YZNOPQRSTUVWX"),
"F": ("ABCDEFGHIJKLM", "YZNOPQRSTUVWX"),
"G": ("ABCDEFGHIJKLM", "XYZNOPQRSTUVW"),
"H": ("ABCDEFGHIJKLM", "XYZNOPQRSTUVW"),
"I": ("ABCDEFGHIJKLM", "WXYZNOPQRSTUV"),
"J": ("ABCDEFGHIJKLM", "WXYZNOPQRSTUV"),
"K": ("ABCDEFGHIJKLM", "VWXYZNOPQRSTU"),
"L": ("ABCDEFGHIJKLM", "VWXYZNOPQRSTU"),
"M": ("ABCDEFGHIJKLM", "UVWXYZNOPQRST"),
"N": ("ABCDEFGHIJKLM", "UVWXYZNOPQRST"),
"O": ("ABCDEFGHIJKLM", "TUVWXYZNOPQRS"),
"P": ("ABCDEFGHIJKLM", "TUVWXYZNOPQRS"),
"Q": ("ABCDEFGHIJKLM", "STUVWXYZNOPQR"),
"R": ("ABCDEFGHIJKLM", "STUVWXYZNOPQR"),
"S": ("ABCDEFGHIJKLM", "RSTUVWXYZNOPQ"),
"T": ("ABCDEFGHIJKLM", "RSTUVWXYZNOPQ"),
"U": ("ABCDEFGHIJKLM", "QRSTUVWXYZNOP"),
"V": ("ABCDEFGHIJKLM", "QRSTUVWXYZNOP"),
"W": ("ABCDEFGHIJKLM", "PQRSTUVWXYZNO"),
"X": ("ABCDEFGHIJKLM", "PQRSTUVWXYZNO"),
"Y": ("ABCDEFGHIJKLM", "OPQRSTUVWXYZN"),
"Z": ("ABCDEFGHIJKLM", "OPQRSTUVWXYZN"),
}
def generate_table(key: str) -> list[tuple[str, str]]:
"""
>>> generate_table('marvin') # doctest: +NORMALIZE_WHITESPACE
[('ABCDEFGHIJKLM', 'UVWXYZNOPQRST'), ('ABCDEFGHIJKLM', 'NOPQRSTUVWXYZ'),
('ABCDEFGHIJKLM', 'STUVWXYZNOPQR'), ('ABCDEFGHIJKLM', 'QRSTUVWXYZNOP'),
('ABCDEFGHIJKLM', 'WXYZNOPQRSTUV'), ('ABCDEFGHIJKLM', 'UVWXYZNOPQRST')]
"""
return [alphabet[char] for char in key.upper()]
def encrypt(key: str, words: str) -> str:
"""
>>> encrypt('marvin', 'jessica')
'QRACRWU'
"""
cipher = ""
count = 0
table = generate_table(key)
for char in words.upper():
cipher += get_opponent(table[count], char)
count = (count + 1) % len(table)
return cipher
def decrypt(key: str, words: str) -> str:
"""
>>> decrypt('marvin', 'QRACRWU')
'JESSICA'
"""
return encrypt(key, words)
def get_position(table: tuple[str, str], char: str) -> tuple[int, int]:
"""
>>> get_position(generate_table('marvin')[0], 'M')
(0, 12)
"""
# `char` is either in the 0th row or the 1st row
row = 0 if char in table[0] else 1
col = table[row].index(char)
return row, col
def get_opponent(table: tuple[str, str], char: str) -> str:
"""
>>> get_opponent(generate_table('marvin')[0], 'M')
'T'
"""
row, col = get_position(table, char.upper())
if row == 1:
return table[0][col]
else:
return table[1][col] if row == 0 else char
if __name__ == "__main__":
import doctest
doctest.testmod() # Fist ensure that all our tests are passing...
"""
Demo:
Enter key: marvin
Enter text to encrypt: jessica
Encrypted: QRACRWU
Decrypted with key: JESSICA
"""
key = input("Enter key: ").strip()
text = input("Enter text to encrypt: ").strip()
cipher_text = encrypt(key, text)
print(f"Encrypted: {cipher_text}")
print(f"Decrypted with key: {decrypt(key, cipher_text)}")