-/* --- @ks_derivekey@ --- *
- *
- * Arguments: @octet *k@ = pointer to an output buffer of at least
- * @MAXHASHSZ@ bytes
- * @size_t ksz@ = actual size wanted (for tracing)
- * @const struct rawkey *rk@ = a raw key, as passed into
- * @genkeys@
- * @int dir@ = direction for the key (@DIR_IN@ or @DIR_OUT@)
- * @const char *what@ = label for the key (input to derivation)
- *
- * Returns: ---
- *
- * Use: Derives a session key, for use on incoming or outgoing data.
- * This function is part of a private protocol between @ks_gen@
- * and the bulk crypto transform @genkeys@ operation.
- */
-
-struct rawkey {
- const gchash *hc;
- const octet *k;
- size_t x, y, z;
-};
-
-void ks_derivekey(octet *k, size_t ksz, const struct rawkey *rk,
- int dir, const char *what)
-{
- const gchash *hc = rk->hc;
- ghash *h;
-
- assert(ksz <= hc->hashsz);
- assert(hc->hashsz <= MAXHASHSZ);
- h = GH_INIT(hc);
- GH_HASH(h, "tripe-", 6); GH_HASH(h, what, strlen(what) + 1);
- switch (dir) {
- case DIR_IN:
- GH_HASH(h, rk->k, rk->x);
- GH_HASH(h, rk->k + rk->x, rk->y - rk->x);
- break;
- case DIR_OUT:
- GH_HASH(h, rk->k + rk->x, rk->y - rk->x);
- GH_HASH(h, rk->k, rk->x);
- break;
- default:
- abort();
- }
- GH_HASH(h, rk->k + rk->y, rk->z - rk->y);
- GH_DONE(h, k);
- GH_DESTROY(h);
- IF_TRACING(T_KEYSET, { IF_TRACING(T_CRYPTO, {
- char _buf[32];
- sprintf(_buf, "crypto: %s key %s", dir ? "incoming" : "outgoing", what);
- trace_block(T_CRYPTO, _buf, k, ksz);
- }) })
-}
-