diff --git a/tests/api/test_wolfmath.c b/tests/api/test_wolfmath.c
index 1e4b622727..fa91c2cc97 100644
--- a/tests/api/test_wolfmath.c
+++ b/tests/api/test_wolfmath.c
@@ -199,7 +199,7 @@ int test_wc_export_int(void)
     len = sizeof(buf);
     ExpectIntEQ(mp_init(&mp), MP_OKAY);
     ExpectIntEQ(mp_set_bit(&mp, 257), 0);
-    ExpectIntEQ(wc_export_int(&mp, buf, &len, 0, WC_TYPE_UNSIGNED_BIN),
+    ExpectIntEQ(wc_export_int(&mp, buf, &len, keySz, WC_TYPE_UNSIGNED_BIN),
         WC_NO_ERR_TRACE(BUFFER_E));
 
     mp_clear(&mp);
diff --git a/wolfcrypt/src/wolfmath.c b/wolfcrypt/src/wolfmath.c
index 60cd6b965d..74af4f2d22 100644
--- a/wolfcrypt/src/wolfmath.c
+++ b/wolfcrypt/src/wolfmath.c
@@ -253,14 +253,14 @@ int wc_export_int(mp_int* mp, byte* buf, word32* len, word32 keySz,
     else {
         /* for WC_TYPE_UNSIGNED_BIN keySz is used to zero pad.
          * The key size is always returned as the size */
-        word32 mpSz = 0;
+        int mpSz = 0;
         if (*len < keySz) {
             *len = keySz;
             return BUFFER_E;
         }
         *len = keySz;
-        mpSz = (word32)mp_unsigned_bin_size(mp);
-        if (mpSz > keySz) {
+        mpSz = mp_unsigned_bin_size(mp);
+        if (mpSz < 0 || (word32)mpSz > keySz) {
             return BUFFER_E;
         }
         XMEMSET(buf, 0, *len);