summary refs log tree commit diff
path: root/crypto/src/math/ec/custom/sec/SecP224K1Curve.cs
blob: a9c55090ff3815abc2979be955841e60009e9cde (plain) (blame)
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
127
128
129
130
131
132
133
134
using System;

using Org.BouncyCastle.Math.Raw;
using Org.BouncyCastle.Utilities.Encoders;

namespace Org.BouncyCastle.Math.EC.Custom.Sec
{
    internal class SecP224K1Curve
        : AbstractFpCurve
    {
        public static readonly BigInteger q = new BigInteger(1,
            Hex.Decode("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFE56D"));

        private const int SECP224K1_DEFAULT_COORDS = COORD_JACOBIAN;
        private const int SECP224K1_FE_INTS = 7;

        protected readonly SecP224K1Point m_infinity;

        public SecP224K1Curve()
            : base(q)
        {
            this.m_infinity = new SecP224K1Point(this, null, null);

            this.m_a = FromBigInteger(BigInteger.Zero);
            this.m_b = FromBigInteger(BigInteger.ValueOf(5));
            this.m_order = new BigInteger(1, Hex.Decode("010000000000000000000000000001DCE8D2EC6184CAF0A971769FB1F7"));
            this.m_cofactor = BigInteger.One;
            this.m_coord = SECP224K1_DEFAULT_COORDS;
        }

        protected override ECCurve CloneCurve()
        {
            return new SecP224K1Curve();
        }

        public override bool SupportsCoordinateSystem(int coord)
        {
            switch (coord)
            {
                case COORD_JACOBIAN:
                    return true;
                default:
                    return false;
            }
        }

        public virtual BigInteger Q
        {
            get { return q; }
        }

        public override ECPoint Infinity
        {
            get { return m_infinity; }
        }

        public override int FieldSize
        {
            get { return q.BitLength; }
        }

        public override ECFieldElement FromBigInteger(BigInteger x)
        {
            return new SecP224K1FieldElement(x);
        }

        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, bool withCompression)
        {
            return new SecP224K1Point(this, x, y, withCompression);
        }

        protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
        {
            return new SecP224K1Point(this, x, y, zs, withCompression);
        }

        public override ECLookupTable CreateCacheSafeLookupTable(ECPoint[] points, int off, int len)
        {
            uint[] table = new uint[len * SECP224K1_FE_INTS * 2];
            {
                int pos = 0;
                for (int i = 0; i < len; ++i)
                {
                    ECPoint p = points[off + i];
                    Nat224.Copy(((SecP224K1FieldElement)p.RawXCoord).x, 0, table, pos); pos += SECP224K1_FE_INTS;
                    Nat224.Copy(((SecP224K1FieldElement)p.RawYCoord).x, 0, table, pos); pos += SECP224K1_FE_INTS;
                }
            }

            return new SecP224K1LookupTable(this, table, len);
        }

        private class SecP224K1LookupTable
            : ECLookupTable
        {
            private readonly SecP224K1Curve m_outer;
            private readonly uint[] m_table;
            private readonly int m_size;

            internal SecP224K1LookupTable(SecP224K1Curve outer, uint[] table, int size)
            {
                this.m_outer = outer;
                this.m_table = table;
                this.m_size = size;
            }

            public virtual int Size
            {
                get { return m_size; }
            }

            public virtual ECPoint Lookup(int index)
            {
                uint[] x = Nat224.Create(), y = Nat224.Create();
                int pos = 0;

                for (int i = 0; i < m_size; ++i)
                {
                    uint MASK = (uint)(((i ^ index) - 1) >> 31);

                    for (int j = 0; j < SECP224K1_FE_INTS; ++j)
                    {
                        x[j] ^= m_table[pos + j] & MASK;
                        y[j] ^= m_table[pos + SECP224K1_FE_INTS + j] & MASK;
                    }

                    pos += (SECP224K1_FE_INTS * 2);
                }

                return m_outer.CreateRawPoint(new SecP224K1FieldElement(x), new SecP224K1FieldElement(y), false);
            }
        }
    }
}