diff --git a/src/sha3.js b/src/sha3.js
index 9f22598..e3f9a7e 100644
--- a/src/sha3.js
+++ b/src/sha3.js
@@ -399,7 +399,7 @@
       }
     }
     if (extraBytes) {
-      array[i] = s[i];
+      array[j] = s[i];
       buffer = buffer.slice(0, bytes);
     }
     return buffer;