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   "cell_type": "markdown",
   "id": "9a5e57eb-9521-4b41-ad73-bab3f76c5eb6",
   "metadata": {},
   "source": [
    "# Key Exchange"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "5c685326-c1e6-42e0-ab75-c684e9290551",
   "metadata": {},
   "source": [
    "Using the key exchange API, two parties can securely compute a set of shared keys using their peer's public key and their own secret key."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "53fc113f-c643-47bb-9881-09b6b3fe9026",
   "metadata": {
    "tags": []
   },
   "outputs": [],
   "source": [
    "%load_ext sql"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "dc2a4492-3637-4aa9-91fb-6f6d64e3b810",
   "metadata": {
    "tags": []
   },
   "outputs": [],
   "source": [
    "%config SqlMagic.feedback=False\n",
    "%config SqlMagic.displaycon=False\n",
    "%sql postgresql://postgres@/"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "e2e54e9b-836b-4e4e-a2f7-991d9d1014fc",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[]"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "%%sql \n",
    "CREATE EXTENSION IF NOT EXISTS pgsodium;"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "43256a56-092a-4bd5-ae0c-4afaff394e77",
   "metadata": {},
   "source": [
    "### `crypto_kx_new_keypair()`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "6c0f972b-eabb-409c-8a49-e41b4ff25410",
   "metadata": {},
   "outputs": [],
   "source": [
    "bob = %sql select public, secret from pgsodium.crypto_kx_new_keypair()\n",
    "bob_public, bob_secret = bob[0][0].tobytes(), bob[0][1].tobytes()\n",
    "\n",
    "alice = %sql select public, secret from pgsodium.crypto_kx_new_keypair()\n",
    "alice_public, alice_secret = alice[0][0].tobytes(), alice[0][1].tobytes()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "3b76dd1e-8e7b-4a33-95ac-3cdc339fa6f3",
   "metadata": {},
   "source": [
    "### `crypto_kx_client_session_keys(client_public bytea, client_secret bytea, server_public bytea)`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "4695674a-a704-424e-800a-143a0f5ce94b",
   "metadata": {},
   "outputs": [],
   "source": [
    "bob_keys = %sql select tx, rx from pgsodium.crypto_kx_client_session_keys(:bob_public, :bob_secret, :alice_public)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "b7a87ef7-adc0-4207-81c4-fc3d0f11d47e",
   "metadata": {},
   "source": [
    "### `crypto_kx_server_session_keys(server_public bytea, server_secret bytea, client_public bytea)`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "559f3e93-36a0-4051-a772-af6fd0a688fb",
   "metadata": {},
   "outputs": [],
   "source": [
    "alice_keys = %sql select tx, rx from pgsodium.crypto_kx_server_session_keys(:alice_public, :alice_secret, :bob_public)"
   ]
  }
 ],
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