pdfdocument.py 文件源码

def authenticate_owner_password(self, password):
        # Algorithm 3.7
        password = (password + self.PASSWORD_PADDING)[:32]
        hash = md5.md5(password)
        if self.r >= 3:
            for _ in range(50):
                hash = md5.md5(hash.digest())
        n = 5
        if self.r >= 3:
            n = self.length // 8
        key = hash.digest()[:n]
        if self.r == 2:
            user_password = ARC4.new(key).decrypt(self.o)
        else:
            user_password = self.o
            for i in range(19, -1, -1):
                k = b''.join(chr(ord(c) ^ i) for c in key)
                user_password = ARC4.new(k).decrypt(user_password)
        return self.authenticate_user_password(user_password)