2 * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * This class contains an EC public key, consisting of two elements:
31 * -- an elliptic curve
32 * -- a non-zero point on that curve (called "Pub")
35 public class ECPublicKey : IPublicKey {
37 public ECCurve Curve {
49 public int KeySizeBits {
51 return BigInt.BitLength(curve.SubgroupOrder);
55 public string AlgorithmName {
65 internal MutableECPoint iPub;
68 * Create a new instance with the provided elements. The
69 * constructor verifies that the provided point is part of
72 public ECPublicKey(ECCurve curve, byte[] Pub)
76 iPub = curve.Decode(Pub);
77 if (iPub.IsInfinity) {
78 throw new CryptoException(
79 "Public key point is infinity");
81 hashCode = curve.GetHashCode()
82 ^ (int)BigInt.HashInt(iPub.X)
83 ^ (int)BigInt.HashInt(iPub.Y);
87 * CheckValid() runs the validity tests on the curve, and
88 * verifies that provided point is part of a subgroup with
89 * the advertised subgroup order.
91 public void CheckValid()
94 MutableECPoint P = iPub.Dup();
95 if (P.MulSpecCT(curve.SubgroupOrder) == 0
98 throw new CryptoException(
99 "Public key point not on the defined subgroup");
103 public override bool Equals(object obj)
105 ECPublicKey pk = obj as ECPublicKey;
109 if (hashCode != pk.hashCode) {
112 return iPub.Eq(pk.iPub);
115 public override int GetHashCode()