Substitution Cipher Solvers
Collection
Monoalphabetic Substitution Cipher Solver Models
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5 items
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Updated
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4
This model is for typos in texts and it outputs corrected texts.
Example:
Text with Typos: Whathvhr wh call owr carhaivhrs - doctors, nwrsh practitionhrs, clinicians, - wh nhhd thhm not only to carh, wh nhhd thhm to uh aulh to providh thh riaht valwh.
Corrected Text: Whatever we call our caregivers - doctors, nurse practitioners, clinicians, - we need them not only to care, we need them to be able to provide the right value.
Example Usage:
#Load the model and tokenizer
text = "" #Text with typos here!
inputs = tokenizer(cipher_text, return_tensors="pt", padding=True, truncation=True, max_length=256).to(device)
outputs = model.generate(inputs["input_ids"], max_length=256)
corrected_text = tokenizer.decode(outputs[0], skip_special_tokens=True)
Full Pipeline Usage:
from transformers import AutoTokenizer, AutoModelForSeq2SeqLM
import torch
from string import ascii_lowercase
import Levenshtein
import random
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
tokenizer = AutoTokenizer.from_pretrained("Cipher-AI/Substitution-Cipher-Alphabet-Eng")
alphabet_model = AutoModelForSeq2SeqLM.from_pretrained("Cipher-AI/Substitution-Cipher-Alphabet-Eng").to(device)
correction_model = AutoModelForSeq2SeqLM.from_pretrained("Cipher-AI/AutoCorrect-EN-v2").to(device)
def similarity_percentage(s1, s2):
distance = Levenshtein.distance(s1, s2)
max_len = max(len(s1), len(s2))
similarity = (1 - distance / max_len) * 100
return similarity
def decode(cipher_text, key):
decipher_map = {ascii_lowercase[i]: j for i, j in enumerate(key[:26])}
decipher_map.update({ascii_lowercase[i].upper(): j.upper() for i, j in enumerate(key[:26])})
ans = ''.join(map(lambda x: decipher_map[x] if x in decipher_map else x, cipher_text))
return ans
def model_pass(model, input, max_length=256):
inputs = tokenizer(input, return_tensors="pt", padding=True, truncation=True, max_length=256).to(device)
outputs = model.generate(inputs["input_ids"], max_length=max_length)
result = tokenizer.decode(outputs[0], skip_special_tokens=True)
return result
def decipher(cipher_text, key) -> str:
decipher_map = {ascii_lowercase[i]: j for i, j in enumerate(key[0])}
decipher_map.update({ascii_lowercase[i].upper(): j.upper() for i, j in enumerate(key[0])})
result = ''.join(map(lambda x: decipher_map[x] if x in decipher_map else x, cipher_text[0]))
return result
def cipher(plain_text) -> tuple[str, list]:
alphabet_map = list(ascii_lowercase)
random.shuffle(alphabet_map)
alphabet_map = {i : j for i, j in zip(ascii_lowercase, alphabet_map)}
alphabet_map.update({i.upper() : j.upper() for i, j in alphabet_map.items()})
cipher_text = ''.join(map(lambda x: alphabet_map[x] if x in alphabet_map else x, plain_text))
return cipher_text, alphabet_map
def correct_text(cipher_text, model_output):
cipher_text = cipher_text.split(' ')
model_output = model_output.split(' ')
letter_map = {i: {j: 0 for j in ascii_lowercase} for i in ascii_lowercase}
# Levenstein distance for lenghts of words
n = len(cipher_text)
m = len(model_output)
i = 0
j = 0
dp = [[0 for _ in range(m + 1)] for _ in range(n + 1)]
for i in range(n + 1):
dp[i][0] = i
for j in range(m + 1):
dp[0][j] = j
for i in range(1, n + 1):
for j in range(1, m + 1):
if len(cipher_text[i - 1]) == len(model_output[j - 1]):
dp[i][j] = dp[i - 1][j - 1]
else:
dp[i][j] = min(dp[i - 1][j], dp[i][j - 1], dp[i - 1][j - 1]) + 1
i = n
j = m
while i > 0 and j > 0:
before = min([(0, dp[i - 1][j - 1]), (1, dp[i - 1][j]), (2, dp[i][j - 1])], key=lambda x: x[1])
match before[0]:
case 0:
if dp[i - 1][j - 1] == dp[i][j]:
# If the same we add them to letter map
cipher = cipher_text[i-1]
model_o = model_output[j-1]
for c_letter, m_letter in zip(cipher.lower(), model_o.lower()):
if c_letter in letter_map and m_letter in letter_map[c_letter]:
letter_map[c_letter][m_letter] += 1
i = i - 1
j = j - 1
case 1:
i = i - 1
case 2:
j = j - 1
for letter in ascii_lowercase:
letter_sum = sum(letter_map[letter].values())
if letter_sum == 0:
# That letter wasn't in the text
letter_map[letter] = None
continue
# Sorted from most accuring to least
letter_map[letter] = [(k, v / letter_sum) for k, v in sorted(letter_map[letter].items(), key=lambda item: item[1], reverse=True)]
change_map = {
i : None for i in ascii_lowercase
}
for i in range(len(ascii_lowercase)):
for letter in ascii_lowercase:
if letter_map[letter] is None:
continue # That letter wasn't in the text
# If None then it didn't get substituted earlier
map_letter = letter_map[letter][i][0]
if (letter_map[letter][i][1] > 0 and (change_map[map_letter] is None
or (change_map[map_letter][2] < letter_map[letter][i][1] and change_map[map_letter][1] >= i))):
change_map[map_letter] = (letter, i, letter_map[letter][i][1])
# Letter, iteration, percentage
change_map = {i[1][0]: i[0] for i in change_map.items() if i[1] is not None}
for letter in ascii_lowercase:
if letter not in change_map:
change_map[letter] = '.'
# Add uppercases
change_map.update(
{
i[0].upper() : i[1].upper() for i in change_map.items()
}
)
new_text = []
for cipher in cipher_text:
new_word = ""
for c_letter in cipher:
if c_letter in change_map:
new_word += change_map[c_letter]
else:
new_word += c_letter
new_text.append(new_word)
return ' '.join(new_text)
def crack_sub(cipher_text):
output = model_pass(alphabet_model, cipher_text, 26)
decoded = decode(cipher_text, output)
second_pass = model_pass(correction_model, decoded, len(decoded))
second_text = correct_text(cipher_text, second_pass)
third_pass = model_pass(correction_model, second_text, len(decoded))
return third_pass
"""
Use crack_sub() function to solve monoalphabetic substitution ciphers!
"""