diff --git a/extensions/xt_pknock.c b/extensions/xt_pknock.c
index a833878..6bb13ca 100644
--- a/extensions/xt_pknock.c
+++ b/extensions/xt_pknock.c
@@ -70,7 +70,12 @@ static struct proc_dir_entry *pde = NULL;
 
 static DEFINE_SPINLOCK(list_lock);
 
-static struct ipt_pknock_crypto crypto = {
+static struct {
+	char				*algo;
+	struct crypto_hash	*tfm;
+	int					size;
+	struct hash_desc	desc;
+} crypto = {
 	.algo	= "hmac(sha256)",
 	.tfm	= NULL,
 	.size	= 0
diff --git a/extensions/xt_pknock.h b/extensions/xt_pknock.h
index a798edb..4b542a4 100644
--- a/extensions/xt_pknock.h
+++ b/extensions/xt_pknock.h
@@ -74,15 +74,6 @@ struct ipt_pknock_rule {
 	unsigned long		max_time; /* max matching time between ports */
 };
 
-#include <linux/crypto.h>
-
-struct ipt_pknock_crypto {
-	char				*algo;
-	struct crypto_hash	*tfm;
-	int					size;
-	struct hash_desc	desc;
-};
-
 struct transport_data {
 	uint8_t	proto;
 	uint16_t	port;	/* destination port */