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@ -1366,8 +1366,7 @@ class PDFDocument(object):
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def process_with_aes(self, key, encrypt, data, repetitions = 1, iv = None):
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if iv is None:
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keylen = len(key)
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iv = bytes([0x00]*keylen)
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iv = bytes(bytearray(16))
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aes = AES.new(key, AES.MODE_CBC, iv)
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@ -1395,10 +1394,18 @@ class PDFDocument(object):
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raise Exception("K1 < 32 ...")
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#def process_with_aes(self, key: bytes, encrypt: bool, data: bytes, repetitions: int = 1, iv: bytes = None):
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E = self.process_with_aes(K[:16], True, K1, 64, K[16:32])
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K = (hashlib.sha256, hashlib.sha384, hashlib.sha512)[sum(E) % 3](E).digest()
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E = bytearray(E)
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E_mod_3 = 0
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for i in range(16):
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E_mod_3 += E[i]
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E_mod_3 %= 3
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K = (hashlib.sha256, hashlib.sha384, hashlib.sha512)[E_mod_3](E).digest()
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if round_number >= 64:
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ch = int.from_bytes(E[-1:], "big", signed=False)
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ch = E[-1:][0] # get last byte
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if ch <= round_number - 32:
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done = True
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