diff --git a/lib/dingtalk/client.rb b/lib/dingtalk/client.rb
new file mode 100644
index 0000000..0964f03
--- /dev/null
+++ b/lib/dingtalk/client.rb
@@ -0,0 +1,24 @@
+module Dingtalk
+  class Client
+    attr_accessor :corp_id
+
+    def initialize(corp_id)
+      @corp_id = corp_id
+    end
+
+    def decrypt(echo_str)
+      aes_key = Base64.decode64(Dingtalk.suite_aes_key + '=')
+      content, status = Dingtalk::Prpcrypt.decrypt(aes_key, echo_str, Dingtalk.suite_key)
+      # TODO check status
+      JSON.parse(content)
+    end
+
+    def suite
+      Api::Suite.new
+    end
+
+    def department
+      Api::Department.new(@corp_id)
+    end
+  end
+end
diff --git a/lib/dingtalk/config.rb b/lib/dingtalk/config.rb
index 5fb7ece..ec008a4 100644
--- a/lib/dingtalk/config.rb
+++ b/lib/dingtalk/config.rb
@@ -18,9 +18,13 @@ module Dingtalk
     def suite_secret
       @suite_secret ||= config.suite_secret
     end
+
+    def suite_aes_key
+      @suite_aes_key ||= config.suite_aes_key
+    end
   end
 
   class Config
-    attr_accessor :redis, :redis_options, :suite_key, :suite_secret
+    attr_accessor :redis, :redis_options, :suite_key, :suite_secret, :suite_aes_key
   end
 end
--
libgit2 0.21.0