diff --git a/wolfcrypt/src/sp_int.c b/wolfcrypt/src/sp_int.c
index cd1db57eb..5a8222a52 100644
--- a/wolfcrypt/src/sp_int.c
+++ b/wolfcrypt/src/sp_int.c
@@ -14207,6 +14207,9 @@ static int _sp_exptmod_nct(const sp_int* b, const sp_int* e, const sp_int* m,
     if (bits > 450) {
         winBits = 6;
     }
+    else if (bits <= 21) {
+        winBits = 2;
+    }
     else if (bits <= 36) {
         winBits = 3;
     }