- * If we didn't get a supported sig, assume there is one with the
- * same name as the key type.
+ * We perform two iterations:
+ *
+ * 1. Do the normal signature fetch, using the fetching data given by
+ * the EVP_PKEY_CTX.
+ * 2. Do the provider specific signature fetch, from the same provider
+ * as |ctx->keymgmt|
+ *
+ * We then try to fetch the keymgmt from the same provider as the
+ * signature, and try to export |ctx->pkey| to that keymgmt (when
+ * this keymgmt happens to be the same as |ctx->keymgmt|, the export
+ * is a no-op, but we call it anyway to not complicate the code even
+ * more).
+ * If the export call succeeds (returns a non-NULL provider key pointer),
+ * we're done and can perform the operation itself. If not, we perform
+ * the second iteration, or jump to legacy.