diff --git a/implement-brute-force-protection/index.js b/implement-brute-force-protection/index.js
new file mode 100644
index 0000000..f32d890
--- /dev/null
+++ b/implement-brute-force-protection/index.js
@@ -0,0 +1,20 @@
+// https://www.codewars.com/kata/implement-brute-force-protection/javascript
+
+const bruteForceDetected = (() => {
+  const failedAttemps = {};
+  return loginReq => {
+    if (loginReq.successful) {
+      if (loginReq.sourceIP in failedAttemps) {
+        failedAttemps[loginReq.sourceIP] = 0;
+      }
+      return false;
+    }
+    if (loginReq.sourceIP in failedAttemps) {
+      const cnt = failedAttemps[loginReq.sourceIP] + 1;
+      failedAttemps[loginReq.sourceIP] = cnt;
+      return 20 <= cnt;
+    }
+    failedAttemps[loginReq.sourceIP] = 1;
+    return false;
+  };
+})();