aboutsummaryrefslogtreecommitdiff
path: root/pyecsca/ec/model.py
blob: 6e79c9b3e0444d2885522f440b2da076e2e5843a (plain)
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
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
from ast import parse, Expression, Module
from pkg_resources import resource_listdir, resource_isdir, resource_stream
from public import public
from typing import List, MutableMapping

from .coordinates import EFDCoordinateModel, CoordinateModel


class CurveModel(object):
    name: str
    coordinates: MutableMapping[str, CoordinateModel]
    parameter_names: List[str]
    coordinate_names: List[str]
    equation: Expression
    base_addition: List[Module]
    base_doubling: List[Module]
    base_negation: List[Module]
    base_neutral: List[Module]
    full_weierstrass: List[Module]
    to_weierstrass: List[Module]
    from_weierstrass: List[Module]

    #TODO: move the base_formulas into methods, operatin on affine points?
    #      Also to_weierstrass anf from_weierstrass.

    # TODO: __eq__


class EFDCurveModel(CurveModel):
    _efd_name: str
    _loaded: bool = False

    def __init__(self, efd_name: str):
        self._efd_name = efd_name
        if self._loaded:
            return
        self.__class__._loaded = True
        self.__class__.coordinates = {}
        self.__class__.parameter_names = []
        self.__class__.coordinate_names = []
        self.__class__.base_addition = []
        self.__class__.base_doubling = []
        self.__class__.base_negation = []
        self.__class__.base_neutral = []
        self.__class__.full_weierstrass = []
        self.__class__.to_weierstrass = []
        self.__class__.from_weierstrass = []

        files = resource_listdir(__name__, "efd/" + efd_name)
        for fname in files:
            file_path = "efd/" + efd_name + "/" + fname
            if resource_isdir(__name__, file_path):
                self.__read_coordinate_dir(self.__class__, file_path, fname)
            else:
                self.__read_curve_file(self.__class__, file_path)

    def __read_curve_file(self, cls, file_path):
        def format_eq(line, mode="exec"):
            return parse(line.replace("^", "**"), mode=mode)

        with resource_stream(__name__, file_path) as f:
            line = f.readline()
            while line:
                line = line.decode("ascii")[:-1]
                if line.startswith("name"):
                    cls.name = line[5:]
                elif line.startswith("parameter"):
                    cls.parameter_names.append(line[10:])
                elif line.startswith("coordinate"):
                    cls.coordinate_names.append(line[11:])
                elif line.startswith("satisfying"):
                    cls.equation = format_eq(line[11:], mode="eval")
                elif line.startswith("addition"):
                    cls.base_addition.append(format_eq(line[9:]))
                elif line.startswith("doubling"):
                    cls.base_doubling.append(format_eq(line[9:]))
                elif line.startswith("negation"):
                    cls.base_negation.append(format_eq(line[9:]))
                elif line.startswith("neutral"):
                    cls.base_neutral.append(format_eq(line[8:]))
                elif line.startswith("toweierstrass"):
                    cls.to_weierstrass.append(format_eq(line[14:]))
                elif line.startswith("fromweierstrass"):
                    cls.from_weierstrass.append(format_eq(line[16:]))
                else:
                    cls.full_weierstrass.append(format_eq(line))
                line = f.readline()

    def __read_coordinate_dir(self, cls, dir_path, name):
        cls.coordinates[name] = EFDCoordinateModel(dir_path, name, self)

    def __eq__(self, other):
        if not isinstance(other, EFDCurveModel):
            return False
        return self._efd_name == other._efd_name

    def __repr__(self):
        return f"{self.__class__.__name__}()"


@public
class ShortWeierstrassModel(EFDCurveModel):

    def __init__(self):
        super().__init__("shortw")


@public
class MontgomeryModel(EFDCurveModel):

    def __init__(self):
        super().__init__("montgom")


@public
class EdwardsModel(EFDCurveModel):

    def __init__(self):
        super().__init__("edwards")


@public
class TwistedEdwardsModel(EFDCurveModel):

    def __init__(self):
        super().__init__("twisted")