diff --git a/library/psa_util.c b/library/psa_util.c
index ad5c9fb..e69ff6b 100644
--- a/library/psa_util.c
+++ b/library/psa_util.c
@@ -494,8 +494,8 @@
         return ret;
     }
 
-    /* Skip leading zeros */
-    while (*p == 0x00) {
+    /* Skip possible leading zero */
+    if (*p == 0x00) {
         p++;
         unpadded_len--;
         /* It should never happen that the input number is all zeros. */