2023-12-26 15:14:57 +01:00
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import re
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import random
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from Crypto.Util.number import long_to_bytes
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values = {}
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with open("output.txt", "r") as f:
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lines = f.read().split("\n")
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values["sum"] = int(lines[0])
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for line in lines[1:]:
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match = re.match(r"(\w+)=(-?[0-9]+)", line)
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values[match[1]] = int(match[2])
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for y in range(0, 1000+1):
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random.seed(y)
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grade = random.choice([2,3])
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a = random.randint(9999, 999999)
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b = random.randint(8888, 888888)
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c = random.randint(7777, 777777)
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if a + b + c == values["sum"]:
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print("[+] Found y:", y)
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break
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print("[+] a:", a)
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print("[+] b:", b)
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print("[+] c:", c)
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print("[+] grade:", grade)
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x = var("x", domain="integer")
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if grade == 2:
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y_x = a*x**2+b*x+c
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if grade == 3:
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d = random.randint(6666, 666666)
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y_x = a*x**3+b*x**2+c*x+d
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print("[+] d:", d)
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print("[+] polynome:", y_x)
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N = values["N"]
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hint = values["hint"]
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p = None
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2023-12-26 15:33:18 +01:00
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q = var("q")
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2023-12-26 15:14:57 +01:00
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for x in range(0,1000+1):
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eq = (N/q)^3 - q^8 + y_x(x=x) == hint
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2023-12-26 15:33:18 +01:00
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solution = solve(eq, q, solution_dict=True)
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2023-12-26 15:14:57 +01:00
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if solution and q in solution[0]:
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print("[+] Found x:", x)
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q = int(solution[0][q])
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p = N//q
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break
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if p is None:
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print("[-] Could not find p and q")
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exit()
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phi_n = (p - 1) * (q - 1)
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d = pow(values["e"], -1, phi_n)
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pt = pow(values["encrypted"], d, values["N"])
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flag = long_to_bytes(pt).decode()
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print("[+] Flag:", flag)
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