diff --git a/wolfcrypt/src/idea.c b/wolfcrypt/src/idea.c
index f7284c8ee..d7ab766d7 100644
--- a/wolfcrypt/src/idea.c
+++ b/wolfcrypt/src/idea.c
@@ -106,7 +106,8 @@ static INLINE word16 idea_invmod(word16 x)
         d += IDEA_MODULO;
 
     /* d must be < IDEA_MODULO */
-    d %= IDEA_MODULO;
+    while (d >= (int)IDEA_MODULO)
+        d -= IDEA_MODULO;
 
     return (word16)(d & IDEA_MASK);
 }