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"""
This module provides functions for runtime configuration of the toolkit.
This includes how errors are handled, or which :py:class:`~pyecsca.ec.mod.Mod` implementation is used.
"""
from copy import deepcopy
from contextvars import ContextVar, Token
from public import public
@public
class ECConfig:
"""Configuration for the :py:mod:`pyecsca.ec` package."""
_no_inverse_action: str = "error"
_non_residue_action: str = "error"
_unsatisfied_formula_assumption_action: str = "error"
_unsatisfied_coordinate_assumption_action: str = "error"
_mod_implementation: str = "gmp"
@property
def no_inverse_action(self) -> str:
"""
Return or set the action to take when a non-invertible element is to be inverted.
One of:
- ``"error"``: Raise :py:class:`pyecsca.ec.error.NonInvertibleError`.
- ``"warning"``: Raise :py:class:`pyecsca.ec.error.NonInvertibleWarning`.
- ``"ignore"``: Ignore the event and compute as if nothing happened.
"""
return self._no_inverse_action
@no_inverse_action.setter
def no_inverse_action(self, value: str):
if value not in ("error", "warning", "ignore"):
raise ValueError("Action has to be one of 'error', 'warning', 'ignore'.")
self._no_inverse_action = value
@property
def non_residue_action(self) -> str:
"""
Return or set the action to take when a the square-root of a non-residue is to be computed.
One of:
- ``"error"``: Raise :py:class:`pyecsca.ec.error.NonResidueError`.
- ``"warning"``: Raise :py:class:`pyecsca.ec.error.NonResidueWarning`.
- ``"ignore"``: Ignore the event and compute as if nothing happened.
"""
return self._non_residue_action
@non_residue_action.setter
def non_residue_action(self, value: str):
if value not in ("error", "warning", "ignore"):
raise ValueError("Action has to be one of 'error', 'warning', 'ignore'.")
self._non_residue_action = value
@property
def unsatisfied_formula_assumption_action(self) -> str:
"""
Return or set the action to take when a formula assumption is unsatisfied during execution.
This works for assumption that can be ignored without a fatal error,
which are those that are not used to compute a value of an undefined parameter.
For example, things of the form ``Z1 = 1``.
One of:
- ``"error"``: Raise :py:class:`pyecsca.ec.error.UnsatisfiedAssumptionError`.
- ``"warning"``: Raise :py:class:`pyecsca.ec.error.UnsatisfiedAssumptionWarning`.
- ``"ignore"``: Ignore the event and compute as if nothing happened.
"""
return self._unsatisfied_formula_assumption_action
@unsatisfied_formula_assumption_action.setter
def unsatisfied_formula_assumption_action(self, value: str):
if value not in ("error", "warning", "ignore"):
raise ValueError("Action has to be one of 'error', 'warning', 'ignore'.")
self._unsatisfied_formula_assumption_action = value
@property
def unsatisfied_coordinate_assumption_action(self) -> str:
"""
Return or set the action to take when a coordinate assumption is unsatisfied during curve creation.
This works for assumption that can be ignored without a fatal error,
which are those that are not used to compute a value of an undefined parameter.
For example, things of the form ``a = -1``.
One of:
- ``"error"``: Raise :py:class:`pyecsca.ec.error.UnsatisfiedAssumptionError`.
- ``"warning"``: Raise :py:class:`pyecsca.ec.error.UnsatisfiedAssumptionWarning`.
- ``"ignore"``: Ignore the event and compute as if nothing happened.
"""
return self._unsatisfied_coordinate_assumption_action
@unsatisfied_coordinate_assumption_action.setter
def unsatisfied_coordinate_assumption_action(self, value: str):
if value not in ("error", "warning", "ignore"):
raise ValueError("Action has to be one of 'error', 'warning', 'ignore'.")
self._unsatisfied_coordinate_assumption_action = value
@property
def mod_implementation(self) -> str:
"""
Return or set the selected :py:class:`pyecsca.ec.mod.Mod` implementation.
One of:
- ``"gmp"``: Requires the GMP library and `gmpy2` package.
- ``"python"``: Doesn't require anything.
"""
return self._mod_implementation
@mod_implementation.setter
def mod_implementation(self, value: str):
if value not in ("python", "gmp"):
raise ValueError("Bad Mod implementaiton, can be one of 'python' or 'gmp'.")
self._mod_implementation = value
@public
class Config:
"""Runtime configuration for the library."""
ec: ECConfig
"""Configuration for the :py:mod:`pyecsca.ec` package."""
def __init__(self):
self.ec = ECConfig()
_config: ContextVar[Config] = ContextVar("config", default=Config())
@public
def getconfig() -> Config:
"""
Get the current config.
:return: The current config.
"""
return _config.get()
@public
def setconfig(cfg: Config) -> Token:
"""
Set the current config.
:param cfg: The config to set.
:return: A token that can be used to reset the config to the previous one.
"""
return _config.set(cfg)
@public
def resetconfig(token: Token) -> None:
"""
Reset the config to the previous one.
:param token: A token from :py:func:`setconfig()`.
"""
_config.reset(token)
@public
class TemporaryConfig:
"""
Temporary config context manager.
Can be entered as follows:
.. code-block:: python
with TemporaryConfig() as cfg:
cfg.some_property = some_value
...
"""
def __init__(self):
self.token = None
self.new_config = deepcopy(getconfig())
def __enter__(self) -> Config:
self.token = setconfig(self.new_config)
return self.new_config
def __exit__(self, t, v, tb):
resetconfig(self.token)
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