diff --git a/include/sxt/sxtkey.h b/include/sxt/sxtkey.h
index a480d90..8386fef 100644
--- a/include/sxt/sxtkey.h
+++ b/include/sxt/sxtkey.h
@@ -48,6 +48,7 @@ typedef struct sxtkey_type {
   uint8_t flags;
   ed25519_pubkey *pubkey;
   ed25519_privkey *privkey;
+  uint64_t hash;
   void *priv;
 } sxtkey_t;