diff --git a/library/arc4.c b/library/arc4.c
index 07665ad..488ddf7 100644
--- a/library/arc4.c
+++ b/library/arc4.c
@@ -143,7 +143,7 @@
 
         memcpy( ibuf, arc4_test_pt[i], 8 );
 
-        arc4_setup( &ctx, (unsigned char *) arc4_test_key[i], 8 );
+        arc4_setup( &ctx, arc4_test_key[i], 8 );
         arc4_crypt( &ctx, 8, ibuf, obuf );
 
         if( memcmp( obuf, arc4_test_ct[i], 8 ) != 0 )