Source code for pycoin.ecdsa.Point

[docs]class NoSuchPointError(ValueError): pass
[docs]class Point(tuple): """ A point on an elliptic curve. This is a subclass of tuple (forced to a 2-tuple), and also includes a reference to the underlying Curve. This class supports the operators ``+``, ``-`` (unary and binary) and ``*``. :param x: x coordinate :param y: y coordinate :param curve: the :class:`Curve <pycoin.ecdsa.Curve.Curve>` this point must be on The constructor raises :class:`NoSuchPointError` if the point is invalid. The point at infinity is ``(x, y) == (None, None)``. """ def __new__(self, x, y, curve): """ Subclasses of tuple require __new__ to be overridden. """ return tuple.__new__(self, (x, y)) def __init__(self, x, y, curve): self._curve = curve super(Point, self).__init__() self.check_on_curve()
[docs] def check_on_curve(self): """raise :class:`NoSuchPointError` if the point is not actually on the curve.""" if not self._curve.contains_point(*self): raise NoSuchPointError('({},{}) is not on the curve {}'.format(self[0], self[1], self._curve))
[docs] def __add__(self, other): """Add one point to another point.""" return self._curve.add(self, other)
[docs] def __sub__(self, other): """Subtract one point from another point.""" return self._curve.add(self, -other)
[docs] def __mul__(self, e): """Multiply a point by an integer.""" return self._curve.multiply(self, e)
def __rmul__(self, other): """Multiply a point by an integer.""" return self * other
[docs] def __neg__(self): """Unary negation""" return self.__class__(self[0], self._curve.p()-self[1], self._curve)
[docs] def curve(self): """:return: the :class:`Curve <pycoin.ecdsa.Curve>` this point is on""" return self._curve