46 lines
1.8 KiB
Python
46 lines
1.8 KiB
Python
from dataclasses import dataclass
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from typing import ClassVar
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from src.models import KeypadSize
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from src.utils import generate_random_nonrepeating_list
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@dataclass
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class CustomerCipher:
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prop_key: list[int]
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set_key: list[int]
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keypad_size: KeypadSize
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MAX_KEYS: ClassVar[int] = 256
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MAX_PROP_PER_KEY: ClassVar[int] = 256
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def __post_init__(self):
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self.check_keys_vs_props()
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def check_keys_vs_props(self) -> None:
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if self.keypad_size.is_dispersable:
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raise ValueError("number of keys must be less than the number of "
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"properties per key to be dispersion resistant")
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@classmethod
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def create(cls, keypad_size: KeypadSize) -> 'CustomerCipher':
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if keypad_size.numb_of_keys > cls.MAX_KEYS or keypad_size.props_per_key > cls.MAX_PROP_PER_KEY:
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raise ValueError(f"Keys and properties per key must not exceed {cls.MAX_KEYS}")
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return cls(
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prop_key=generate_random_nonrepeating_list(keypad_size.numb_of_props),
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set_key=generate_random_nonrepeating_list(keypad_size.props_per_key),
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keypad_size=keypad_size,
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)
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def renew(self):
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self.prop_key = generate_random_nonrepeating_list(self.keypad_size.numb_of_props)
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self.set_key = generate_random_nonrepeating_list(self.keypad_size.props_per_key)
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def get_prop_set_val(self, prop: int) -> int:
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assert (prop in self.prop_key)
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prop_idx = self.prop_key.index(prop)
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set_idx = prop_idx % self.keypad_size.props_per_key
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return self.set_key[set_idx]
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def get_set_index(self, set_val: int) -> int:
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if set_val not in self.set_key:
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raise ValueError(f"Set value {set_val} not found in set values")
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return self.set_key.index(set_val) |