bool BotanDH::deriveKey(SymmetricKey **ppSymmetricKey, PublicKey* publicKey, PrivateKey* privateKey)
{
// Check parameters
if ((ppSymmetricKey == NULL) ||
(publicKey == NULL) ||
(privateKey == NULL))
{
return false;
}
// Get keys
Botan::DH_PublicKey* pub = ((BotanDHPublicKey*) publicKey)->getBotanKey();
Botan::DH_PrivateKey* priv = ((BotanDHPrivateKey*) privateKey)->getBotanKey();
if (pub == NULL || priv == NULL)
{
ERROR_MSG("Failed to get Botan DH keys");
return false;
}
// Derive the secret
Botan::SymmetricKey sk;
try
{
Botan::PK_Key_Agreement ka(*priv, "Raw");
sk = ka.derive_key(0, pub->public_value());
}
catch (...)
{
ERROR_MSG("Botan DH key agreement failed");
return false;
}
ByteString secret;
secret.resize(sk.length());
memcpy(&secret[0], sk.begin(), sk.length());
*ppSymmetricKey = new SymmetricKey(sk.length() * 8);
if (*ppSymmetricKey == NULL)
{
ERROR_MSG("Can't create DH secret");
return false;
}
if (!(*ppSymmetricKey)->setKeyBits(secret))
{
delete *ppSymmetricKey;
*ppSymmetricKey = NULL;
return false;
}
return true;
}
bool BotanDH::deriveKey(SymmetricKey **ppSymmetricKey, PublicKey* publicKey, PrivateKey* privateKey)
{
// Check parameters
if ((ppSymmetricKey == NULL) ||
(publicKey == NULL) ||
(privateKey == NULL))
{
return false;
}
// Get keys
Botan::DH_PublicKey* pub = ((BotanDHPublicKey*) publicKey)->getBotanKey();
BotanDH_PrivateKey* priv = ((BotanDHPrivateKey*) privateKey)->getBotanKey();
if (pub == NULL || priv == NULL || priv->impl == NULL)
{
ERROR_MSG("Failed to get Botan DH keys");
return false;
}
// Derive the secret
Botan::SymmetricKey sk;
try
{
#if BOTAN_VERSION_CODE >= BOTAN_VERSION_CODE_FOR(1,11,33)
BotanRNG* rng = (BotanRNG*)BotanCryptoFactory::i()->getRNG();
Botan::PK_Key_Agreement ka(*priv->impl, *rng->getRNG(), "Raw");
#else
Botan::PK_Key_Agreement ka(*priv->impl, "Raw");
#endif
sk = ka.derive_key(0, pub->public_value());
}
catch (std::exception& e)
{
ERROR_MSG("Botan DH key agreement failed: %s", e.what());
return false;
}
ByteString secret;
// We compensate that Botan removes leading zeros
int size = ((BotanDHPublicKey*) publicKey)->getOutputLength();
int keySize = sk.length();
secret.wipe(size);
memcpy(&secret[0] + size - keySize, sk.begin(), keySize);
*ppSymmetricKey = new SymmetricKey(secret.size() * 8);
if (*ppSymmetricKey == NULL)
{
ERROR_MSG("Can't create DH secret");
return false;
}
if (!(*ppSymmetricKey)->setKeyBits(secret))
{
delete *ppSymmetricKey;
*ppSymmetricKey = NULL;
return false;
}
return true;
}
