From 643eaad6259c7685dfe1494494a968bba9e3580c Mon Sep 17 00:00:00 2001 From: Vinicius Cordeiro Date: Wed, 20 Oct 2021 20:16:17 -0300 Subject: [PATCH 1/3] Add Bifid cipher --- ciphers/bifid.py | 110 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 ciphers/bifid.py diff --git a/ciphers/bifid.py b/ciphers/bifid.py new file mode 100644 index 000000000000..58312d088eec --- /dev/null +++ b/ciphers/bifid.py @@ -0,0 +1,110 @@ +#!/usr/bin/env python3 + +""" +The Bifid Cipher uses a Polybius Square to encipher a message in a way that +makes it fairly difficult to decipher without knowing the secret. + +https://www.braingle.com/brainteasers/codes/bifid.php +""" + +import numpy as np + + +class BifidCipher: + def __init__(self): + SQUARE = [ + ["a", "b", "c", "d", "e"], + ["f", "g", "h", "i", "k"], + ["l", "m", "n", "o", "p"], + ["q", "r", "s", "t", "u"], + ["v", "w", "x", "y", "z"], + ] + self.SQUARE = np.array(SQUARE) + + def letter_to_numbers(self, letter: str) -> np.ndarray: + """ + Return the pair of numbers that represents the given letter in the + polybius square + + >>> np.array_equal(BifidCipher().letter_to_numbers('a'), [1,1]) + True + + >>> np.array_equal(BifidCipher().letter_to_numbers('u'), [4,5]) + True + """ + index1, index2 = np.where(self.SQUARE == letter) + indexes = np.concatenate([index1 + 1, index2 + 1]) + return indexes + + def numbers_to_letter(self, index1: int, index2: int) -> str: + """ + Return the letter corresponding to the position [index1, index2] in + the polybius square + + >>> BifidCipher().numbers_to_letter(4, 5) == "u" + True + + >>> BifidCipher().numbers_to_letter(1, 1) == "a" + True + """ + letter = self.SQUARE[index1 - 1, index2 - 1] + return letter + + def encode(self, message: str) -> str: + """ + Return the encoded version of message according to the polybius cipher + + >>> BifidCipher().encode('testmessage') == 'qtltbdxrxlk' + True + + >>> BifidCipher().encode('Test Message') == 'qtltbdxrxlk' + True + + >>> BifidCipher().encode('test j') == BifidCipher().encode('test i') + True + """ + message = message.lower() + message = message.replace(" ", "") + message = message.replace("j", "i") + + first_step = np.empty((2, len(message))) + for letter_index in range(len(message)): + numbers = self.letter_to_numbers(message[letter_index]) + + first_step[0, letter_index] = numbers[0] + first_step[1, letter_index] = numbers[1] + + second_step = first_step.reshape(2 * len(message)) + encoded_message = "" + for numbersIndex in range(len(message)): + index1 = int(second_step[numbersIndex * 2]) + index2 = int(second_step[(numbersIndex * 2) + 1]) + letter = self.numbers_to_letter(index1, index2) + encoded_message = encoded_message + letter + + return encoded_message + + def decode(self, message: str) -> str: + """ + Return the decoded version of message according to the polybius cipher + + >>> BifidCipher().decode('qtltbdxrxlk') == 'testmessage' + True + """ + message = message.lower() + message.replace(" ", "") + first_step = np.empty(2 * len(message)) + for letter_index in range(len(message)): + numbers = self.letter_to_numbers(message[letter_index]) + first_step[letter_index * 2] = numbers[0] + first_step[letter_index * 2 + 1] = numbers[1] + + second_step = first_step.reshape((2, len(message))) + decoded_message = "" + for numbersIndex in range(len(message)): + index1 = int(second_step[0, numbersIndex]) + index2 = int(second_step[1, numbersIndex]) + letter = self.numbers_to_letter(index1, index2) + decoded_message = decoded_message + letter + + return decoded_message From eebd7a1156fd1149571c012bb8ccad0cf66ee4a4 Mon Sep 17 00:00:00 2001 From: Vinicius Cordeiro Date: Wed, 20 Oct 2021 20:21:25 -0300 Subject: [PATCH 2/3] Add missing type hint --- ciphers/bifid.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/ciphers/bifid.py b/ciphers/bifid.py index 58312d088eec..404a040e9e09 100644 --- a/ciphers/bifid.py +++ b/ciphers/bifid.py @@ -11,7 +11,7 @@ class BifidCipher: - def __init__(self): + def __init__(self) -> None: SQUARE = [ ["a", "b", "c", "d", "e"], ["f", "g", "h", "i", "k"], From e29c606c4b69e2b6467917889e58d8bf3e217bf6 Mon Sep 17 00:00:00 2001 From: Vinicius Cordeiro Date: Wed, 20 Oct 2021 20:23:39 -0300 Subject: [PATCH 3/3] Fix variable names --- ciphers/bifid.py | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/ciphers/bifid.py b/ciphers/bifid.py index 404a040e9e09..c1b071155917 100644 --- a/ciphers/bifid.py +++ b/ciphers/bifid.py @@ -76,9 +76,9 @@ def encode(self, message: str) -> str: second_step = first_step.reshape(2 * len(message)) encoded_message = "" - for numbersIndex in range(len(message)): - index1 = int(second_step[numbersIndex * 2]) - index2 = int(second_step[(numbersIndex * 2) + 1]) + for numbers_index in range(len(message)): + index1 = int(second_step[numbers_index * 2]) + index2 = int(second_step[(numbers_index * 2) + 1]) letter = self.numbers_to_letter(index1, index2) encoded_message = encoded_message + letter @@ -101,9 +101,9 @@ def decode(self, message: str) -> str: second_step = first_step.reshape((2, len(message))) decoded_message = "" - for numbersIndex in range(len(message)): - index1 = int(second_step[0, numbersIndex]) - index2 = int(second_step[1, numbersIndex]) + for numbers_index in range(len(message)): + index1 = int(second_step[0, numbers_index]) + index2 = int(second_step[1, numbers_index]) letter = self.numbers_to_letter(index1, index2) decoded_message = decoded_message + letter