DHBW/Krypto_Grundlagen
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✨ Added comments and bruteforce example

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David Huh 2021-10-18 11:42:09 +02:00
parent 78afa2c967
commit 1ea46419ca
1 changed files with 50 additions and 8 deletions
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58
Verschiebe-Chiffre.py
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@ -1,13 +1,48 @@
def encrypt_text(cleartext: str = 'Bitcoin', incrementation: int = 13): def encrypt_text(cleartext: str = 'Bitcoin', incrementation: int = 13):
encrypted_text = '' """
This method encrypts a text by shifting each letter by the value of incrementation
:param cleartext: The secret message to encrypt
:param incrementation: How much the letters should be shifted
:return: Encrypted text
"""
return shift_text(cleartext, (incrementation % 26)) # '%' to repeat after 26 with 0
def decrypt_text(encrypted_text: str = 'Ovgpbva', incrementation: int = 13):
"""
This method decrypts a text by shifting each letter by the value of incrementation
:param encrypted_text: The encrypted secret message to decrypt
:param incrementation: How much the letters should be shifted
:return: Decrypted text
"""
return shift_text(encrypted_text, 26 - (incrementation % 26)) # '%' to repeat after 26 with 0
def shift_text(cleartext: str, incrementation: int):
"""
This method shifts every letter of a string by the value of incrementation
:param cleartext: The string to be shifted
:param incrementation: How much the letters should be shifted
:return: Shifted text
"""
shifted_text = ''
for char in cleartext: for char in cleartext:
encrypted_text += increment_char(char, incrementation) shifted_text += increment_char(char, incrementation)
return encrypted_text return shifted_text
def increment_char(char, incrementation: int = 1): def increment_char(char, incrementation: int = 1):
"""
This method shifts one char by the value of incrementation
:param char: Char to be shifted
:param incrementation: How much the char should be shifted
:return: Shifted letter
"""
# converting character to byte # converting character to byte
char_in_bytes = bytes(char, 'utf-8')[0] char_in_bytes = bytes(char, 'utf-8')[0]
if char_in_bytes + incrementation >= 91 and char_in_bytes < 91 \ if char_in_bytes + incrementation >= 91 and char_in_bytes < 91 \
@ -19,15 +54,22 @@ def increment_char(char, incrementation: int = 1):
return str(new_char_in_bytes)[2] return str(new_char_in_bytes)[2]
def decrypt_text(encrypted_text: str = 'Ovgpbva', incrementation: int = 13): def brute_force_example(cleartext: str = 'Bitcoin', incrementation: int = 7):
cleartext = '' """
This is an example of how to bruteforce an encrypted text. (Encrypted with Letter-Shifting)
for char in encrypted_text: :param cleartext: The secret message to encrypt and decrypt during bruteforcing
cleartext += increment_char(char, 26 - incrementation) :param incrementation: How much the letters should be shifted
"""
encrypted_text = encrypt_text(cleartext, incrementation=incrementation)
return cleartext for x in range(26):
if cleartext == decrypt_text(encrypted_text, incrementation=x):
print(f'Text was shifted by {x} letters.')
if __name__ == '__main__': if __name__ == '__main__':
print(encrypt_text()) print(encrypt_text())
print(decrypt_text()) print(decrypt_text())
brute_force_example()