diff --git a/ct.c b/ct.c
index 3dd6e43..047a448 100644
--- a/ct.c
+++ b/ct.c
@@ -18,10 +18,13 @@
 
 
 uint32_t
-lc_ct_cmp(const uint8_t *x, const uint8_t *y, size_t l)
+lc_ct_cmp(const void *px, const void *py, size_t l)
 {
-	uint32_t	r = 0;
+	const unsigned char	*x, *y;
+	unsigned char		 r = 0;
 
+	x = px;
+	y = py;
 	for (; l > 0; l--)
 		r |= *x++ ^ *y++;
 
diff --git a/lilcrypto.h b/lilcrypto.h
index b68d8fe..f811e2d 100644
--- a/lilcrypto.h
+++ b/lilcrypto.h
@@ -146,7 +146,7 @@ struct lc_hkdf_params {
 
 /* Constant-time operations */
 
-uint32_t	lc_ct_cmp(const uint8_t *, const uint8_t *, size_t);
+uint32_t	lc_ct_cmp(const void *, const void *, size_t);
 uint32_t	lc_ct_mask32(uint32_t);