diff --git a/ReadMe.md b/ReadMe.md
index 0c06591..52ddcc6 100644
--- a/ReadMe.md
+++ b/ReadMe.md
@@ -28,7 +28,7 @@ import { User, UserModel } from '../../model/User';
 type UserDetailPageProps = User & JWTProps & RouterProps;
 
 export const getServerSideProps = compose<{ id: string }, UserDetailPageProps>(
-    jwtVerifier(),
+    jwtVerifier(), // set `JWT_SECRET` in `.env.local` first
     cache(),
     errorLogger,
     router,
diff --git a/package.json b/package.json
index 5010ffb..11a301b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "next-ssr-middleware",
-    "version": "0.6.0",
+    "version": "0.6.1",
     "license": "LGPL-3.0-or-later",
     "author": "shiy2008@gmail.com",
     "description": "Koa-like middlewares for Next.js Server Side Rendering",
diff --git a/source/middleware.ts b/source/middleware.ts
index c1af0f8..6b03f4d 100644
--- a/source/middleware.ts
+++ b/source/middleware.ts
@@ -58,7 +58,7 @@ export interface JWTProps<T extends DataObject = {}> {
 
 export function jwtVerifier<I extends DataObject, O extends DataObject = {}>(
     tokenKey = 'token',
-    secretKey = 'JWT_TOKEN',
+    secretKey = 'JWT_SECRET',
     options: VerifyOptions = {}
 ): Middleware<I, O & JWTProps> {
     return async ({ req: { url, cookies } }, next) => {