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/*
* PKCS#11 ECDH
* (C) 2016 Daniel Neus, Sirrix AG
* (C) 2016 Philipp Weber, Sirrix AG
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/p11_ecdh.h>
#if defined(BOTAN_HAS_ECDH)
#include <botan/internal/p11_mechanism.h>
#include <botan/der_enc.h>
#include <botan/pk_ops.h>
#include <botan/rng.h>
namespace Botan {
namespace PKCS11 {
ECDH_PublicKey PKCS11_ECDH_PublicKey::export_key() const
{
return ECDH_PublicKey(domain(), public_point());
}
ECDH_PrivateKey PKCS11_ECDH_PrivateKey::export_key() const
{
auto priv_key = get_attribute_value(AttributeType::Value);
Null_RNG rng;
return ECDH_PrivateKey(rng, domain(), BigInt::decode(priv_key));
}
secure_vector<uint8_t> PKCS11_ECDH_PrivateKey::private_key_bits() const
{
return export_key().private_key_bits();
}
namespace {
class PKCS11_ECDH_KA_Operation final : public PK_Ops::Key_Agreement
{
public:
PKCS11_ECDH_KA_Operation(const PKCS11_EC_PrivateKey& key, const std::string& params)
: PK_Ops::Key_Agreement(), m_key(key), m_mechanism(MechanismWrapper::create_ecdh_mechanism(params))
{}
size_t agreed_value_size() const override { return m_key.domain().get_p_bytes(); }
/// The encoding in V2.20 was not specified and resulted in different implementations choosing different encodings.
/// 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.
secure_vector<uint8_t> agree(size_t key_len, const uint8_t other_key[], size_t other_key_len, const uint8_t salt[],
size_t salt_len) override
{
std::vector<uint8_t> der_encoded_other_key;
if(m_key.point_encoding() == PublicPointEncoding::Der)
{
DER_Encoder(der_encoded_other_key).encode(other_key, other_key_len, OCTET_STRING);
m_mechanism.set_ecdh_other_key(der_encoded_other_key.data(), der_encoded_other_key.size());
}
else
{
m_mechanism.set_ecdh_other_key(other_key, other_key_len);
}
if(salt != nullptr && salt_len > 0)
{
m_mechanism.set_ecdh_salt(salt, salt_len);
}
ObjectHandle secret_handle = 0;
AttributeContainer attributes;
attributes.add_bool(AttributeType::Sensitive, false);
attributes.add_bool(AttributeType::Extractable, true);
attributes.add_numeric(AttributeType::Class, static_cast< CK_OBJECT_CLASS >(ObjectClass::SecretKey));
attributes.add_numeric(AttributeType::KeyType, static_cast< CK_KEY_TYPE >(KeyType::GenericSecret));
attributes.add_numeric(AttributeType::ValueLen, static_cast< CK_ULONG >(key_len));
m_key.module()->C_DeriveKey(m_key.session().handle(), m_mechanism.data(), m_key.handle(), attributes.data(),
static_cast<Ulong>(attributes.count()), &secret_handle);
Object secret_object(m_key.session(), secret_handle);
secure_vector<uint8_t> secret = secret_object.get_attribute_value(AttributeType::Value);
if(secret.size() < key_len)
{
throw PKCS11_Error("ECDH key derivation secret length is too short");
}
secret.resize(key_len);
return secret;
}
private:
const PKCS11_EC_PrivateKey& m_key;
MechanismWrapper m_mechanism;
};
}
std::unique_ptr<PK_Ops::Key_Agreement>
PKCS11_ECDH_PrivateKey::create_key_agreement_op(RandomNumberGenerator&,
const std::string& params,
const std::string& /*provider*/) const
{
return std::unique_ptr<PK_Ops::Key_Agreement>(new PKCS11_ECDH_KA_Operation(*this, params));
}
PKCS11_ECDH_KeyPair generate_ecdh_keypair(Session& session, const EC_PublicKeyGenerationProperties& pub_props,
const EC_PrivateKeyGenerationProperties& priv_props)
{
ObjectHandle pub_key_handle = 0;
ObjectHandle priv_key_handle = 0;
Mechanism mechanism = { static_cast< CK_MECHANISM_TYPE >(MechanismType::EcKeyPairGen), nullptr, 0 };
session.module()->C_GenerateKeyPair(session.handle(), &mechanism,
pub_props.data(), static_cast<Ulong>(pub_props.count()),
priv_props.data(), static_cast<Ulong>(priv_props.count()),
&pub_key_handle, &priv_key_handle);
return std::make_pair(PKCS11_ECDH_PublicKey(session, pub_key_handle), PKCS11_ECDH_PrivateKey(session, priv_key_handle));
}
}
}
#endif