1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
from copy import copy
from typing import Mapping
from .context import Context
from .curve import EllipticCurve
from .formula import Formula, AdditionFormula, DoublingFormula, ScalingFormula
from .point import Point
class ScalarMultiplier(object):
curve: EllipticCurve
formulas: Mapping[str, Formula]
context: Context
def __init__(self, curve: EllipticCurve, ctx: Context = None, **formulas: Formula):
for formula in formulas.values():
if formula is not None and formula.coordinate_model is not curve.coordinate_model:
raise ValueError
self.curve = curve
if ctx:
self.context = ctx
else:
self.context = Context()
self.formulas = dict(formulas)
def multiply(self, scalar: int, point: Point) -> Point:
raise NotImplementedError
class LTRMultiplier(ScalarMultiplier):
always: bool
def __init__(self, curve: EllipticCurve, add: AdditionFormula, dbl: DoublingFormula,
scl: ScalingFormula = None,
ctx: Context = None, always: bool = False):
super().__init__(curve, ctx, add=add, dbl=dbl, scl=scl)
self.always = always
def multiply(self, scalar: int, point: Point) -> Point:
pass
class RTLMultiplier(ScalarMultiplier):
always: bool
def __init__(self, curve: EllipticCurve, add: AdditionFormula, dbl: DoublingFormula,
scl: ScalingFormula = None,
ctx: Context = None, always: bool = False):
super().__init__(curve, ctx, add=add, dbl=dbl, scl=scl)
self.always = always
def multiply(self, scalar: int, point: Point) -> Point:
q = copy(point)
r = copy(self.curve.neutral)
while scalar > 0:
q = self.context.execute(self.formulas["dbl"], q, **self.curve.parameters)
if scalar & 1 != 0:
r = self.context.execute(self.formulas["add"], q, r, **self.curve.parameters)
elif self.always:
self.context.execute(self.formulas["add"], q, r, **self.curve.parameters)
scalar >>= 1
return r
|
