diff --git a/src/Utils/Service/OssService.php b/src/Utils/Service/OssService.php
new file mode 100644
index 0000000..afd3f43
--- /dev/null
+++ b/src/Utils/Service/OssService.php
@@ -0,0 +1,131 @@
+<?php
+/**
+ * OssService.php@LuxStudio
+ *
+ * @author 李东云<dongyun.li@luxcreo.cn>
+ * Powered by PhpStorm
+ * Created on 2022/5/11
+ */
+
+namespace Singularity\HDK\Utils\Service;
+
+use Hyperf\Utils\Codec\Json;
+
+class OssService
+{
+    /**
+     * @const 30s 过期
+     */
+    public const EXPIRE = 30;
+    
+    protected string $accessKeyId;
+    protected string $accessKeySecret;
+    protected string $host;
+    
+    public function __construct()
+    {
+        $this->accessKeyId = config('common.third_party.storage.oss.access_key_id');
+        $this->accessKeySecret = config('common.third_party.storage.oss.access_key_secret');
+        $this->host = config('common.third_party.storage.oss.oss_host');
+    }
+    
+    /**
+     * 生成签证
+     *
+     * @param string|null $dir
+     * @param bool        $isImage
+     * @param int         $maxFileSize 最大文件大小（单位：b）
+     *
+     * @return array
+     */
+    public function generatePolicy(
+        string $dir = null,
+        bool $isImage = false,
+        int $maxFileSize = 1048576000
+    ): array {
+        $expire_time = time() + self::EXPIRE;
+        $expiration = $this->gmtIso8601($expire_time);
+        
+        //最大文件大小.用户可以自己设置
+        $condition = [
+            0 => 'Content-Length-Range',
+            1 => 0,
+            2 => $maxFileSize,
+        ];
+        $conditions[] = $condition;
+        
+        // 表示用户上传的数据，必须是以$dir开始，不然上传会失败，这一步不是必须项，只是为了安全起见，防止用户通过policy上传到别人的目录。
+        if ($dir) {
+            $start = [
+                0 => 'starts-with',
+                1 => '$key',
+                2 => $dir,
+            ];
+            $conditions[] = $start;
+        }
+        
+        
+        $policy = Json::encode([
+            'expiration' => $expiration,
+            'conditions' => $conditions,
+        ]);
+        $base64_policy = base64_encode($policy);
+        $string_to_sign = $base64_policy;
+        $signature = base64_encode(hash_hmac('sha1', $string_to_sign, $this->accessKeySecret, true));
+        
+        $callback = Json::encode([
+            'callbackUrl' => config('oss_callback'),
+            'callbackBody' => $isImage ? <<<'callbackBody'
+{
+    "bucket": ${bucket},
+    "object": ${object},
+    "etag": ${etag},
+    "size": ${size},
+    "mimeType": ${mimeType},
+    "imageInfo": {
+        "height": ${imageInfo.height},
+        "width": ${imageInfo.width},
+        "format": ${imageInfo.format}
+    },
+    "uid": ${x:uid},
+    "name": ${x:name},
+    "hash": ${x:hash}
+}
+callbackBody: <<<'callbackBody'
+{
+    "bucket": ${bucket},
+    "object": ${object},
+    "etag": ${etag},
+    "size": ${size},
+    "mimeType": ${mimeType},
+    "uid": ${x:uid},
+    "name": ${x:name},
+    "hash": ${x:hash}
+}
+callbackBody,
+            'callbackBodyType' => 'application/json',
+        ]);
+        
+        return [
+            'accessid' => $this->accessKeyId,
+            'host' => $this->host,
+            'policy' => $base64_policy,
+            'signature' => $signature,
+            'expire' => $expire_time,
+            'dir' => $dir,
+            'callback' => base64_encode($callback),
+        ];
+    }
+    
+    /**
+     * 将时间戳转化为 ISO8601 格式
+     *
+     * @param int $time
+     *
+     * @return string
+     */
+    protected function gmtIso8601(int $time): string
+    {
+        return str_replace('+00:00', '.000Z', gmdate('c', $time));
+    }
+}
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