Simple fun Demo of Frequency Analysis w/ a Substitution Cipher

Substitution_Cipher_Freq_Analysis_Hack.py

# Sample ciphertext for practice
cipher_text = "muzbpbxyenryzamvrbrzctbmxznhvzeojmvbjjzctbzhnxwrzhnowrzknzqxnovrzqzkxbqczrbqwzuqjcbxzctqvzmczrnbj"

# Function to help you make preliminary guesses of what some cipher symbols are.
# Collects the character frequency of all letters in the ciphertext
def freq(cipher_text):
  result = {}
  for ch in cipher_text:
    if ch in result:
        result[ch] += 1
    else:
        result[ch] = 1
  return result

# Gives the plaintext when attempting to decrypt cipher_text using your own 
# pattern that's in a dictionary format (see example below)
def substitute(pattern, cipher_text):
  cipher_text_chars = list(cipher_text)
  pattern_symbols = list(pattern.keys())
  
  result = []

  for ch in cipher_text_chars:
    if (ch in pattern_symbols):
      result.append(pattern[ch].upper())
    else:
      result.append(ch)
        
  return ''.join(result)

# Cipher to test. Edit values here to try different letter combinations.
# This is what I came up with simply by eyeballing & comparing the ciphertext & hacked plaintext
patt = {
  'z': ' ',
  'c': 't',
  't': 'h',
  'b': 'e',
  'q': 'a',
  'v': 'n',
  'm': 'i',
  'u': 'f',
  'x': 'r',
  'j': 's',
  'n': 'o',
  'o': 'u',
  'r': 'd',
  'a': 'm',
  'h': 'w',
  'e': 'b',
  'w': 'l',
  'p': 'v',
  'y': 'y',
  'k': 'g'
}

# To analyze the pattern before hacking. 
# High frequency letters are typically vowels/space.
print(freq(cipher_text))

# Print out decrypted ciphertext to test
print('Original:\n' + cipher_text + '\n')
print('Hacked:\n' + substitute(patt, cipher_text))