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
|
/*
* ECDH implemenation
* (C) 2007 Manuel Hartl, FlexSecure GmbH
* 2007 Falko Strenzke, FlexSecure GmbH
* 2008-2010 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/ecdh.h>
#include <botan/internal/pk_ops_impl.h>
#if defined(BOTAN_HAS_OPENSSL)
#include <botan/internal/openssl.h>
#endif
namespace Botan {
namespace {
/**
* ECDH operation
*/
class ECDH_KA_Operation : public PK_Ops::Key_Agreement_with_KDF
{
public:
ECDH_KA_Operation(const ECDH_PrivateKey& key, const std::string& kdf, RandomNumberGenerator& rng) :
PK_Ops::Key_Agreement_with_KDF(kdf),
m_curve(key.domain().get_curve()),
m_cofactor(key.domain().get_cofactor()),
m_order(key.domain().get_order()),
m_rng(rng)
{
m_l_times_priv = inverse_mod(m_cofactor, m_order) * key.private_value();
}
secure_vector<uint8_t> raw_agree(const uint8_t w[], size_t w_len) override
{
PointGFp point = OS2ECP(w, w_len, m_curve);
PointGFp S = m_cofactor * point;
Blinded_Point_Multiply blinder(S, m_order);
S = blinder.blinded_multiply(m_l_times_priv, m_rng);
BOTAN_ASSERT(S.on_the_curve(), "ECDH agreed value was on the curve");
return BigInt::encode_1363(S.get_affine_x(), m_curve.get_p().bytes());
}
private:
const CurveGFp& m_curve;
const BigInt& m_cofactor;
const BigInt& m_order;
BigInt m_l_times_priv;
RandomNumberGenerator& m_rng;
};
}
std::unique_ptr<PK_Ops::Key_Agreement>
ECDH_PrivateKey::create_key_agreement_op(RandomNumberGenerator& rng,
const std::string& params,
const std::string& provider) const
{
#if defined(BOTAN_HAS_OPENSSL)
if(provider == "openssl" || provider.empty())
{
try
{
return make_openssl_ecdh_ka_op(*this, params);
}
catch(Lookup_Error&)
{
if(provider == "openssl")
throw;
}
}
#endif
if(provider == "base" || provider.empty())
return std::unique_ptr<PK_Ops::Key_Agreement>(new ECDH_KA_Operation(*this, params, rng));
throw Provider_Not_Found(algo_name(), provider);
}
}
|
