/*

* CECPQ1 (x25519 + NewHope)

* (C) 2016 Jack Lloyd

*

* Botan is released under the Simplified BSD License (see license.txt)

*/

#include <botan/cecpq1.h>

#include <botan/newhope.h>

#include <botan/curve25519.h>

#include <botan/rng.h>

namespace Botan {

void CECPQ1_offer(uint8_t send[CECPQ1_OFFER_BYTES],

                  CECPQ1_key* offer_key_output,

                  RandomNumberGenerator& rng)

   {

   offer_key_output->m_x25519 = rng.random_vec(32);

   curve25519_basepoint(send, offer_key_output->m_x25519.data());

   newhope_keygen(send + 32, &offer_key_output->m_newhope,

                  rng, Newhope_Mode::BoringSSL);

   }

void CECPQ1_accept(uint8_t shared_key[CECPQ1_SHARED_KEY_BYTES],

                   uint8_t send[CECPQ1_ACCEPT_BYTES],

                   const uint8_t received[CECPQ1_OFFER_BYTES],

                   RandomNumberGenerator& rng)

   {

   secure_vector<uint8_t> x25519_key = rng.random_vec(32);

   curve25519_basepoint(send, x25519_key.data());

   curve25519_donna(shared_key, x25519_key.data(), received);

   newhope_sharedb(shared_key + 32, send + 32, received + 32,

                   rng, Newhope_Mode::BoringSSL);

   }

void CECPQ1_finish(uint8_t shared_key[CECPQ1_SHARED_KEY_BYTES],

                   const CECPQ1_key& offer_key,

                   const uint8_t received[CECPQ1_ACCEPT_BYTES])

   {

   curve25519_donna(shared_key, offer_key.m_x25519.data(), received);

   newhope_shareda(shared_key + 32, &offer_key.m_newhope, received + 32,

                   Newhope_Mode::BoringSSL);

   }

}