diff --git a/chacha-poly1305.c b/chacha-poly1305.c
index cb95bf7bd4f0593f5743ac1bcec1e3d5e066162b..83be9ee86885dd97e6d8d74e047298357e5f3e71 100644
--- a/chacha-poly1305.c
+++ b/chacha-poly1305.c
@@ -44,6 +44,8 @@
 
 #define CHACHA_ROUNDS 20
 
+/* FIXME: Also set nonce to zero, and implement nonce
+   auto-increment? */
 void
 chacha_poly1305_set_key (struct chacha_poly1305_ctx *ctx,
 			 const uint8_t *key)