diff --git a/build/konami-card.js b/build/konami-card.js
index b81b477..eb9039c 100644
--- a/build/konami-card.js
+++ b/build/konami-card.js
@@ -1,3 +1,9 @@
+crypto.getRandomValues = (buf) => {
+  buf = Buffer.from(buf);
+  let bytes = crypto.randomBytes(buf.length);
+  buf.set(bytes);
+  return buf;
+};
 require('./wasm_exec');
 
 const go = new Go();
@@ -8,17 +14,17 @@ const wasmInstance = new WebAssembly.Instance(wasmModule, go.importObject);
 go.run(wasmInstance).then();
 
 module.exports.encode = function (nfcId) {
-  return new Promise(resolve => {
+  return new Promise((resolve) => {
     KONAMI_CARD_ENCODE(nfcId, function (result) {
-      resolve(result)
-    })
-  })
+      resolve(result);
+    });
+  });
 };
 
 module.exports.decode = function (cardId) {
-  return new Promise(resolve => {
+  return new Promise((resolve) => {
     KONAMI_CARD_DECODE(cardId, function (result) {
-      resolve(result)
-    })
-  })
+      resolve(result);
+    });
+  });
 };