Botan  2.8.0
Crypto and TLS for C++11
p11_ecdh.cpp
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1 /*
2 * PKCS#11 ECDH
3 * (C) 2016 Daniel Neus, Sirrix AG
4 * (C) 2016 Philipp Weber, Sirrix AG
5 *
6 * Botan is released under the Simplified BSD License (see license.txt)
7 */
8 
9 #include <botan/p11_ecdh.h>
10 
11 #if defined(BOTAN_HAS_ECDH)
12 
13 #include <botan/internal/p11_mechanism.h>
14 #include <botan/der_enc.h>
15 #include <botan/pk_ops.h>
16 #include <botan/rng.h>
17 
18 namespace Botan {
19 
20 namespace PKCS11 {
21 
22 ECDH_PublicKey PKCS11_ECDH_PublicKey::export_key() const
23  {
24  return ECDH_PublicKey(domain(), public_point());
25  }
26 
27 ECDH_PrivateKey PKCS11_ECDH_PrivateKey::export_key() const
28  {
29  auto priv_key = get_attribute_value(AttributeType::Value);
30 
31  Null_RNG rng;
32  return ECDH_PrivateKey(rng, domain(), BigInt::decode(priv_key));
33  }
34 
35 secure_vector<uint8_t> PKCS11_ECDH_PrivateKey::private_key_bits() const
36  {
37  return export_key().private_key_bits();
38  }
39 
40 namespace {
41 class PKCS11_ECDH_KA_Operation final : public PK_Ops::Key_Agreement
42  {
43  public:
44  PKCS11_ECDH_KA_Operation(const PKCS11_EC_PrivateKey& key, const std::string& params)
45  : PK_Ops::Key_Agreement(), m_key(key), m_mechanism(MechanismWrapper::create_ecdh_mechanism(params))
46  {}
47 
48  size_t agreed_value_size() const override { return m_key.domain().get_p_bytes(); }
49 
50  /// The encoding in V2.20 was not specified and resulted in different implementations choosing different encodings.
51  /// Applications relying only on a V2.20 encoding (e.g. the DER variant) other than the one specified now (raw) may not work with all V2.30 compliant tokens.
52  secure_vector<uint8_t> agree(size_t key_len, const uint8_t other_key[], size_t other_key_len, const uint8_t salt[],
53  size_t salt_len) override
54  {
55  std::vector<uint8_t> der_encoded_other_key;
56  if(m_key.point_encoding() == PublicPointEncoding::Der)
57  {
58  der_encoded_other_key = DER_Encoder().encode(other_key, other_key_len, OCTET_STRING).get_contents_unlocked();
59  m_mechanism.set_ecdh_other_key(der_encoded_other_key.data(), der_encoded_other_key.size());
60  }
61  else
62  {
63  m_mechanism.set_ecdh_other_key(other_key, other_key_len);
64  }
65 
66  if(salt != nullptr && salt_len > 0)
67  {
68  m_mechanism.set_ecdh_salt(salt, salt_len);
69  }
70 
71  ObjectHandle secret_handle = 0;
72  AttributeContainer attributes;
73  attributes.add_bool(AttributeType::Sensitive, false);
74  attributes.add_bool(AttributeType::Extractable, true);
75  attributes.add_numeric(AttributeType::Class, static_cast< CK_OBJECT_CLASS >(ObjectClass::SecretKey));
76  attributes.add_numeric(AttributeType::KeyType, static_cast< CK_KEY_TYPE >(KeyType::GenericSecret));
77  attributes.add_numeric(AttributeType::ValueLen, key_len);
78  m_key.module()->C_DeriveKey(m_key.session().handle(), m_mechanism.data(), m_key.handle(), attributes.data(),
79  attributes.count(), &secret_handle);
80 
81  Object secret_object(m_key.session(), secret_handle);
82  secure_vector<uint8_t> secret = secret_object.get_attribute_value(AttributeType::Value);
83  if(secret.size() < key_len)
84  {
85  throw PKCS11_Error("ECDH key derivation secret length is too short");
86  }
87  secret.resize(key_len);
88  return secret;
89  }
90 
91  private:
92  const PKCS11_EC_PrivateKey& m_key;
93  MechanismWrapper m_mechanism;
94  };
95 
96 }
97 
98 std::unique_ptr<PK_Ops::Key_Agreement>
99 PKCS11_ECDH_PrivateKey::create_key_agreement_op(RandomNumberGenerator&,
100  const std::string& params,
101  const std::string& /*provider*/) const
102  {
103  return std::unique_ptr<PK_Ops::Key_Agreement>(new PKCS11_ECDH_KA_Operation(*this, params));
104  }
105 
106 PKCS11_ECDH_KeyPair generate_ecdh_keypair(Session& session, const EC_PublicKeyGenerationProperties& pub_props,
107  const EC_PrivateKeyGenerationProperties& priv_props)
108  {
109  ObjectHandle pub_key_handle = 0;
110  ObjectHandle priv_key_handle = 0;
111 
112  Mechanism mechanism = { static_cast< CK_MECHANISM_TYPE >(MechanismType::EcKeyPairGen), nullptr, 0 };
113 
114  session.module()->C_GenerateKeyPair(session.handle(), &mechanism,
115  pub_props.data(), pub_props.count(), priv_props.data(), priv_props.count(),
116  &pub_key_handle, &priv_key_handle);
117 
118  return std::make_pair(PKCS11_ECDH_PublicKey(session, pub_key_handle), PKCS11_ECDH_PrivateKey(session, priv_key_handle));
119  }
120 
121 }
122 }
123 
124 #endif
CK_ULONG CK_MECHANISM_TYPE
Definition: pkcs11t.h:583
int(* final)(unsigned char *, CTX *)
size_t salt_len
Definition: x509_obj.cpp:26
Definition: alg_id.cpp:13
CK_OBJECT_HANDLE ObjectHandle
Definition: p11.h:846
static BigInt decode(const uint8_t buf[], size_t length)
Definition: bigint.h:713
CK_MECHANISM Mechanism
Definition: p11.h:839
const RSA_PrivateKey & m_key
Definition: rsa.cpp:277