// Encrypts plaintext ptxt, stores as ciphertext ctxt
void encrypt_phrase(dheluks_ctx_t *ctx, dheluks_pkg_t *pkg, dheluks_kys_t *skr, dheluks_txt_t *txt) {
chacha_poly1305_set_key(&ctx->ciph, skr->sharekey); //set key
gen_random(&ctx->rand, NONCE_SIZE, pkg->nonce); //generate nonce
chacha_poly1305_set_nonce(&ctx->ciph, pkg->nonce); //set nonce
chacha_poly1305_encrypt(&ctx->ciph, pkg->csize, pkg->cphtxt, txt->plntxt); //encrypt
chacha_poly1305_digest(&ctx->ciph, DIGEST_SIZE, pkg->digest);
}
// Send a record (datagram version, accepts all record types, handles encryption and authentication).
static bool send_record_priv_datagram(sptps_t *s, uint8_t type, const void *data, uint16_t len) {
char buffer[len + 21UL];
// Create header with sequence number, length and record type
uint32_t seqno = s->outseqno++;
uint32_t netseqno = ntohl(seqno);
memcpy(buffer, &netseqno, 4);
buffer[4] = type;
memcpy(buffer + 5, data, len);
if(s->outstate) {
// If first handshake has finished, encrypt and HMAC
chacha_poly1305_encrypt(s->outcipher, seqno, buffer + 4, len + 1, buffer + 4, NULL);
return s->send_data(s->handle, type, buffer, len + 21UL);
} else {
// Otherwise send as plaintext
return s->send_data(s->handle, type, buffer, len + 5UL);
}
}
