diff --git a/package.json b/package.json
index 01fdda1..caa5609 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "unlock-music",
   "version": "1.4.1",
-  "updateInfo": "支持.qmc2；qq音乐显示封面图片；界面优化；修复GBK编码ID3信息",
+  "updateInfo": "支持.kwm",
   "license": "MIT",
   "description": "Unlock encrypted music file in browser.",
   "repository": {
diff --git a/src/decrypt/ncm.js b/src/decrypt/ncm.js
index d785bba..9b0cfcb 100644
--- a/src/decrypt/ncm.js
+++ b/src/decrypt/ncm.js
@@ -19,7 +19,8 @@ export async function Decrypt(file, raw_filename, raw_ext) {
     let audioOffset = musicMetaObj.offset + dataView.getUint32(musicMetaObj.offset + 5, true) + 13;
     let audioData = new Uint8Array(fileBuffer, audioOffset);
 
-    for (let cur = 0; cur < audioData.length; ++cur) audioData[cur] ^= keyBox[cur & 0xff];
+    let lenAudioData = audioData.length;
+    for (let cur = 0; cur < lenAudioData; ++cur) audioData[cur] ^= keyBox[cur & 0xff];
 
 
     if (musicMeta.album === undefined) musicMeta.album = "";
diff --git a/src/decrypt/qmc.js b/src/decrypt/qmc.js
index c692c0d..e3c78b2 100644
--- a/src/decrypt/qmc.js
+++ b/src/decrypt/qmc.js
@@ -50,7 +50,6 @@ export async function Decrypt(file, raw_filename, raw_ext) {
         }
     }
 
-    //todo: Use artists list to replace artist
     const info = GetFileInfo(musicMeta.common.artist, musicMeta.common.title, raw_filename);
     if (handler.detect) reportKeyUsage(keyData, seed.Matrix128,
         info.artist, info.title, musicMeta.common.album, raw_filename, raw_ext);
@@ -109,7 +108,7 @@ async function queryAlbumCoverImage(artist, title, album) {
     }
     console.log(queriedSong);
     let imgUrl = "";
-    if (undefined !== queriedSong && undefined !== queriedSong["album"]) {
+    if (!!queriedSong && !!queriedSong["album"]) {
         if (queriedSong["album"]["pmid"] !== undefined) {
             imgUrl = "https://y.gtimg.cn/music/photo_new/T002M000" + queriedSong["album"]["pmid"] + ".jpg"
         } else if (queriedSong["album"]["id"] !== undefined) {
@@ -119,4 +118,4 @@ async function queryAlbumCoverImage(artist, title, album) {
         }
     }
     return imgUrl;
-}
\ No newline at end of file
+}