void NTCPSession::CreateAESKey (uint8_t * pubKey, uint8_t * aesKey)
{
CryptoPP::DH dh (elgp, elgg);
uint8_t sharedKey[256];
if (!dh.Agree (sharedKey, m_DHKeysPair->privateKey, pubKey))
{
LogPrint ("Couldn't create shared key");
Terminate ();
return;
};
if (sharedKey[0] & 0x80)
{
aesKey[0] = 0;
memcpy (aesKey + 1, sharedKey, 31);
}
else if (sharedKey[0])
memcpy (aesKey, sharedKey, 32);
else
{
// find first non-zero byte
uint8_t * nonZero = sharedKey + 1;
while (!*nonZero)
{
nonZero++;
if (nonZero - sharedKey > 32)
{
LogPrint ("First 32 bytes of shared key is all zeros. Ignored");
return;
}
}
memcpy (aesKey, nonZero, 32);
}
}
void NTCPSession::CreateAESKey (uint8_t * pubKey, uint8_t * aesKey)
{
CryptoPP::DH dh (elgp, elgg);
CryptoPP::SecByteBlock secretKey(dh.AgreedValueLength());
if (!dh.Agree (secretKey, i2p::context.GetPrivateKey (), pubKey))
{
LogPrint ("Couldn't create shared key");
Terminate ();
return;
};
if (secretKey[0] & 0x80)
{
aesKey[0] = 0;
memcpy (aesKey + 1, secretKey, 31);
}
else
memcpy (aesKey, secretKey, 32);
}