diff --git a/include/mbedtls/arc4.h b/include/mbedtls/arc4.h
index f11fc5b..83a7461 100644
--- a/include/mbedtls/arc4.h
+++ b/include/mbedtls/arc4.h
@@ -53,7 +53,7 @@
  *            security risk. We recommend considering stronger ciphers instead.
  *
  */
-typedef struct
+typedef struct mbedtls_arc4_context
 {
     int x;                      /*!< permutation index */
     int y;                      /*!< permutation index */