/src/botan/src/lib/pubkey/ecdh/ecdh.cpp
Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * ECDH implemenation |
3 | | * (C) 2007 Manuel Hartl, FlexSecure GmbH |
4 | | * 2007 Falko Strenzke, FlexSecure GmbH |
5 | | * 2008-2010 Jack Lloyd |
6 | | * |
7 | | * Botan is released under the Simplified BSD License (see license.txt) |
8 | | */ |
9 | | |
10 | | #include <botan/ecdh.h> |
11 | | #include <botan/numthry.h> |
12 | | #include <botan/internal/pk_ops_impl.h> |
13 | | |
14 | | namespace Botan { |
15 | | |
16 | | std::unique_ptr<Public_Key> ECDH_PrivateKey::public_key() const |
17 | 0 | { |
18 | 0 | return std::make_unique<ECDH_PublicKey>(domain(), public_point()); |
19 | 0 | } |
20 | | |
21 | | namespace { |
22 | | |
23 | | /** |
24 | | * ECDH operation |
25 | | */ |
26 | | class ECDH_KA_Operation final : public PK_Ops::Key_Agreement_with_KDF |
27 | | { |
28 | | public: |
29 | | |
30 | | ECDH_KA_Operation(const ECDH_PrivateKey& key, const std::string& kdf, RandomNumberGenerator& rng) : |
31 | | PK_Ops::Key_Agreement_with_KDF(kdf), |
32 | | m_group(key.domain()), |
33 | | m_rng(rng) |
34 | 15.1k | { |
35 | 15.1k | m_l_times_priv = m_group.inverse_mod_order(m_group.get_cofactor()) * key.private_value(); |
36 | 15.1k | } |
37 | | |
38 | 0 | size_t agreed_value_size() const override { return m_group.get_p_bytes(); } |
39 | | |
40 | | secure_vector<uint8_t> raw_agree(const uint8_t w[], size_t w_len) override |
41 | 15.1k | { |
42 | 15.1k | PointGFp input_point = m_group.get_cofactor() * m_group.OS2ECP(w, w_len); |
43 | 15.1k | input_point.randomize_repr(m_rng); |
44 | | |
45 | 15.1k | const PointGFp S = m_group.blinded_var_point_multiply( |
46 | 15.1k | input_point, m_l_times_priv, m_rng, m_ws); |
47 | | |
48 | 15.1k | if(S.on_the_curve() == false) |
49 | 0 | throw Internal_Error("ECDH agreed value was not on the curve"); |
50 | 15.1k | return BigInt::encode_1363(S.get_affine_x(), m_group.get_p_bytes()); |
51 | 15.1k | } |
52 | | private: |
53 | | const EC_Group m_group; |
54 | | BigInt m_l_times_priv; |
55 | | RandomNumberGenerator& m_rng; |
56 | | std::vector<BigInt> m_ws; |
57 | | }; |
58 | | |
59 | | } |
60 | | |
61 | | std::unique_ptr<PK_Ops::Key_Agreement> |
62 | | ECDH_PrivateKey::create_key_agreement_op(RandomNumberGenerator& rng, |
63 | | const std::string& params, |
64 | | const std::string& provider) const |
65 | 15.1k | { |
66 | 15.1k | if(provider == "base" || provider.empty()) |
67 | 15.1k | return std::make_unique<ECDH_KA_Operation>(*this, params, rng); |
68 | | |
69 | 0 | throw Provider_Not_Found(algo_name(), provider); |
70 | 15.1k | } |
71 | | |
72 | | |
73 | | } |