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cada743 a935848 cada743 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | from collections import Counter
FREQ = {
"a": 8.167, "b": 1.492, "c": 2.782, "d": 4.253, "e": 12.702,
"f": 2.228, "g": 2.015, "h": 6.094, "i": 6.966, "j": 0.153,
"k": 0.772, "l": 4.025, "m": 2.406, "n": 6.749, "o": 7.507,
"p": 1.929, "q": 0.095, "r": 5.987, "s": 6.327, "t": 9.056,
"u": 2.758, "v": 0.978, "w": 2.360,
"x": 0.150, "y": 1.974, "z": 0.074,
}
def caesar_decrypt(text: str, key: int) -> str:
return "".join(
chr((ord(c) - 65 - key) % 26 + 65) if c.isascii() and c.isupper()
else chr((ord(c) - 97 - key) % 26 + 97) if c.isascii() and c.islower()
else c
for c in text
)
def chi_squared(text: str) -> float:
letters = [c.lower() for c in text if c.isascii() and c.isalpha()]
n = len(letters)
if not n:
return float("inf")
count = Counter(letters)
return sum(
((count.get(c, 0) - (FREQ[c] / 100 * n)) ** 2) / (FREQ[c] / 100 * n)
for c in FREQ
)
def caesar_attack(text: str, progress_callback=None) -> dict:
import time
if progress_callback:
progress_callback(0, 260, "Starting attack...")
results = []
for k in range(26):
if progress_callback:
for step in range(10):
progress_callback((k * 10) + step, 260, f"Testing shift {k} ({step * 10}%)...")
time.sleep(0.005)
score = chi_squared(caesar_decrypt(text, k))
plaintext = caesar_decrypt(text, k)
results.append((k, score, plaintext))
if progress_callback:
progress_callback((k * 10) + 10, 260, f"Testing shift {k} (100%)...")
results.sort(key=lambda x: x[1])
best_key, best_score, best_plaintext = results[0]
if progress_callback:
progress_callback(260, 260, "Complete")
return {
"guessed_key": best_key,
"guessed_plaintext": best_plaintext,
}
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