diff --git a/shopxo/app/plugins/vr_ticket/service/BaseService.php b/shopxo/app/plugins/vr_ticket/service/BaseService.php
index c65a946..b8bdf4b 100644
--- a/shopxo/app/plugins/vr_ticket/service/BaseService.php
+++ b/shopxo/app/plugins/vr_ticket/service/BaseService.php
@@ -399,14 +399,14 @@ class BaseService
     /**
      * 生成短码
      *
-     * 编码结构：goods_id(4位base36) + ticket_id(5位base36) = 9位 → Feistel8 → 短码
-     * - goods_id: 4位 base36 (范围 0-1,679,615，ShopXO 商品上限充足)
-     * - ticket_id: 5位 base36 (范围 0-60,466,175，每商品可发约6000万张票)
-     * - 解码 O(1): 直接取前4位=goods_id，后5位=ticket_id，无需暴力搜索
+     * 编码结构：【明文4位 goods_id】【混淆5位 ticket_id】→ 短码
+     * - 前4位：goods_id 明文 base36 (范围 0-1,679,615)
+     * - 后5位：ticket_id 经 Feistel8 混淆 (范围 0-60,466,175)
+     * - 解码 O(1)：直接读前4位=goods_id，用key解密后5位=ticket_id
      *
      * @param int $goods_id 0-1679615
      * @param int $ticket_id 0-60466175
-     * @return string base36小写短码
+     * @return string base36小写短码（9位）
      * @throws \Exception 参数超范围时抛出
      */
     public static function shortCodeEncode(int $goods_id, int $ticket_id): string
@@ -420,29 +420,31 @@ class BaseService
             throw new \Exception("ticket_id 超出范围 (max=1073741823), given={$ticket_id}");
         }
 
-        // goods_id 固定4位 base36
+        // goods_id 固定4位 base36（明文）
         $goods_part = str_pad(base_convert($goods_id, 10, 36), 4, '0', STR_PAD_LEFT);
-        // ticket_id 固定5位 base36
-        $ticket_part = str_pad(base_convert($ticket_id, 10, 36), 5, '0', STR_PAD_LEFT);
 
-        // 拼接为9位 base36 字符串，转为大整数
-        // 使用 intval(string, 36) 转换
-        $packed_str = $goods_part . $ticket_part;
-        $packed = intval($packed_str, 36);
-
-        // Feistel8 混淆
+        // ticket_id 混淆
+        // ticket_id 填满5位 base36，用 Feistel8 混淆
+        $ticket_int = intval(str_pad(base_convert($ticket_id, 10, 36), 5, '0', STR_PAD_LEFT), 36);
         $key = self::getGoodsKey($goods_id);
-        return strtolower(self::feistelEncode($packed, $key));
+        $obfuscated = self::feistelEncode($ticket_int, $key);
+        // 确保混淆结果也是5位
+        $ticket_part = str_pad($obfuscated, 5, '0', STR_PAD_LEFT);
+
+        // 拼接：前4位明文 goods_id + 后5位混淆 ticket_id
+        return strtolower($goods_part . $ticket_part);
     }
 
     /**
      * 解析短码（解码回 goods_id + ticket_id）
      *
-     * 明文方案：短码经 Feistel8 解密后，前4位=goods_id，后5位=ticket_id
-     * 解码 O(1)，无需暴力搜索
+     * 解码结构：【明文4位 goods_id】【混淆5位 ticket_id】
+     * - 前4位：直接 base36_decode = goods_id
+     * - 后5位：用 goods_id 派生 key → Feistel 解密 = ticket_id
+     * - 解码 O(1)，无暴力搜索
      *
-     * @param string $code 短码（小写或大写均可）
-     * @param int|null $goods_id_hint 可选提示（已不再需要，用于兼容）
+     * @param string $code 短码（小写或大写均可，9位）
+     * @param int|null $goods_id_hint 可选提示（已不需要，用于兼容）
      * @return array ['goods_id' => int, 'ticket_id' => int]
      * @throws \Exception 解码失败时抛出
      */
@@ -450,45 +452,27 @@ class BaseService
     {
         $code = strtolower($code);
 
-        // 如果有 hint，直接用 hint 的 key 解密
-        // 如果没有 hint，暴力搜索（最多尝试 1-100000）
-        $decoded_goods_id = null;
-        $decoded_ticket_id = null;
+        // 前4位：明文 goods_id
+        $goods_part = substr($code, 0, 4);
+        $goods_id = intval($goods_part, 36);
 
-        if ($goods_id_hint !== null) {
-            $key = self::getGoodsKey($goods_id_hint);
-            $packed = self::feistelDecode($code, $key);
-            $packed_str = base_convert($packed, 10, 36);
-            // 前4位 goods_id，后5位 ticket_id
-            $decoded_goods_id = intval(substr($packed_str, 0, 4), 36);
-            $decoded_ticket_id = intval(substr($packed_str, 4, 5), 36);
-            // 验证解码出的 goods_id 是否与 hint 匹配
-            if ($decoded_goods_id !== $goods_id_hint) {
-                throw new \Exception("短码解码失败：hint 不匹配 (code={$code}, hint={$goods_id_hint}, decoded={$decoded_goods_id})");
-            }
-        } else {
-            // 暴力搜索 goods_id（优化：只搜索实际存在的范围）
-            $max_goods = 100000;
-            for ($gid = 1; $gid <= $max_goods; $gid++) {
-                $key = self::getGoodsKey($gid);
-                $packed = self::feistelDecode($code, $key);
-                $packed_str = base_convert($packed, 10, 36);
-                $candidate_goods_id = intval(substr($packed_str, 0, 4), 36);
-                if ($candidate_goods_id === $gid) {
-                    $decoded_goods_id = $gid;
-                    $decoded_ticket_id = intval(substr($packed_str, 4, 5), 36);
-                    break;
-                }
-            }
+        // 校验 hint（如果提供）
+        if ($goods_id_hint !== null && $goods_id !== $goods_id_hint) {
+            throw new \Exception("短码解码失败：hint 不匹配 (code={$code}, hint={$goods_id_hint}, decoded={$goods_id})");
         }
 
-        if ($decoded_goods_id === null) {
-            throw new \Exception("短码解码失败：无法找到匹配的 goods_id (code={$code})");
-        }
+        // 用 goods_id 派生 key
+        $key = self::getGoodsKey($goods_id);
+
+        // 后5位：混淆的 ticket_id → Feistel 解密
+        $ticket_part = substr($code, 4, 5);
+        $ticket_int = self::feistelDecode($ticket_part, $key);
+        // 转回字符串确保5位，然后 decode
+        $ticket_id = intval(str_pad(base_convert($ticket_int, 10, 36), 5, '0', STR_PAD_LEFT), 36);
 
         return [
-            'goods_id'  => $decoded_goods_id,
-            'ticket_id' => $decoded_ticket_id,
+            'goods_id'  => $goods_id,
+            'ticket_id' => $ticket_id,
         ];
     }
 
diff --git a/tests/phase4_1_feistel_test.php b/tests/phase4_1_feistel_test.php
index 1293532..33ac448 100644
--- a/tests/phase4_1_feistel_test.php
+++ b/tests/phase4_1_feistel_test.php
@@ -87,57 +87,41 @@ function shortCodeEncode(int $goods_id, int $ticket_id): string
         throw new Exception("ticket_id 超出范围 (max=1073741823), given={$ticket_id}");
     }
 
-    // goods_id 固定4位 base36，ticket_id 固定5位 base36
+    // goods_id 固定4位 base36（明文）
     $goods_part = str_pad(base_convert($goods_id, 10, 36), 4, '0', STR_PAD_LEFT);
-    $ticket_part = str_pad(base_convert($ticket_id, 10, 36), 5, '0', STR_PAD_LEFT);
 
-    // 拼接为9位 base36 字符串
-    $packed_str = $goods_part . $ticket_part;
-    $packed = intval($packed_str, 36);
-
-    // Feistel8 混淆
+    // ticket_id 混淆
+    $ticket_int = intval(str_pad(base_convert($ticket_id, 10, 36), 5, '0', STR_PAD_LEFT), 36);
     $key = getGoodsKey($goods_id);
-    return strtolower(feistelEncode($packed, $key));
+    $obfuscated = feistelEncode($ticket_int, $key);
+    $ticket_part = str_pad($obfuscated, 5, '0', STR_PAD_LEFT);
+
+    // 拼接：前4位明文 goods_id + 后5位混淆 ticket_id
+    return strtolower($goods_part . $ticket_part);
 }
 
 function shortCodeDecode(string $code, ?int $goods_id_hint = null): array
 {
     $code = strtolower($code);
 
-    $decoded_goods_id = null;
-    $decoded_ticket_id = null;
+    // 前4位：明文 goods_id
+    $goods_part = substr($code, 0, 4);
+    $goods_id = intval($goods_part, 36);
 
-    if ($goods_id_hint !== null) {
-        $key = getGoodsKey($goods_id_hint);
-        $packed = feistelDecode($code, $key);
-        $packed_str = base_convert($packed, 10, 36);
-        // 前4位 goods_id，后5位 ticket_id
-        $decoded_goods_id = intval(substr($packed_str, 0, 4), 36);
-        $decoded_ticket_id = intval(substr($packed_str, 4, 5), 36);
-        if ($decoded_goods_id !== $goods_id_hint) {
-            throw new Exception("短码解码失败：hint 不匹配");
-        }
-    } else {
-        // 暴力搜索
-        $max_goods = 100000;
-        for ($gid = 1; $gid <= $max_goods; $gid++) {
-            $key = getGoodsKey($gid);
-            $packed = feistelDecode($code, $key);
-            $packed_str = base_convert($packed, 10, 36);
-            $candidate_goods_id = intval(substr($packed_str, 0, 4), 36);
-            if ($candidate_goods_id === $gid) {
-                $decoded_goods_id = $gid;
-                $decoded_ticket_id = intval(substr($packed_str, 4, 5), 36);
-                break;
-            }
-        }
+    // 校验 hint（如果提供）
+    if ($goods_id_hint !== null && $goods_id !== $goods_id_hint) {
+        throw new Exception("短码解码失败：hint 不匹配");
     }
 
-    if ($decoded_goods_id === null) {
-        throw new Exception("短码解码失败：无法找到匹配的 goods_id");
-    }
+    // 用 goods_id 派生 key
+    $key = getGoodsKey($goods_id);
 
-    return ['goods_id' => $decoded_goods_id, 'ticket_id' => $decoded_ticket_id];
+    // 后5位：混淆的 ticket_id → Feistel 解密
+    $ticket_part = substr($code, 4, 5);
+    $ticket_int = feistelDecode($ticket_part, $key);
+    $ticket_id = intval(str_pad(base_convert($ticket_int, 10, 36), 5, '0', STR_PAD_LEFT), 36);
+
+    return ['goods_id' => $goods_id, 'ticket_id' => $ticket_id];
 }
 
 function signQrPayload(array $payload): string