近年來因為智慧型手機的日益普及和雲端服務的急速增加，帶動了物聯網產品的快速成長。人們的日常生活上有許多應用和相關情境，需要藉著物聯網產品收集和分析資料來達到需求。物聯網產品會藉著不同的感測器接收不同的資料，例如：使用者的動作、心跳率、溫度，接著將資料透過智慧型手機傳送到雲端。若能藉著智慧型手機直接擷取這些傳送的數據，則可以使得人們大大的提升資料收集的便利。
一般情況下，使用智慧型手機擷取封包都需要有最高權限，但是啟動手機最高權限來擷取封包有相當大的風險，例如：對手機系統產生危害，洩漏隱私訊息風險…等，而且也無法擷取指定的物聯網產品收集到的資料。因此我們實作了一個手機應用程式 -"iCap"，此應用程式不需要使用最高權限來擷取封包。"iCap"會呼叫一個名為VpnService的方法建立一個虛擬網路卡，接著修改路由表讓所有封包導向此虛擬網路卡，並藉此來擷取所有通過虛擬網路卡的網路封包。
"iCap"主要用來分析和過濾並擷取指定的網路封包。根據物聯網產品附加的應用程式，"iCap"分析應用程式的使用者識別碼，用來擷取指定的物聯網產品感測器收集到的資料封包。另外，"iCap"也透過讓使用者可以指定protcol，IP address，port number等條件，讓使用者可以針對特定的目標分析網路封包，協助相關通訊協定的研究與封包異常行為的偵測。

In recent years, whether the Smartphone is the most common device, or clouds service is developing rapidly, they help the growth fast of the Internet of Things (IoT). There are many applications and relevant major scenarios with the need to collect and analyze a lot of data by IoT. Most of IoT product collect the data from a wide variety of different sensors, such as user's movements, heart-rate, and temperature, then send it to the cloud via Smartphones. If we can capture these data directly by Smartphone, it can be more convenient for data collection.
Packet capturing by root the Smartphone is risky for system hazards, privacy leaks, etc., and then cannot capture the packet that receives from the IoT sensor. So we developed an application named "iCap" which uses no root feature to capture the packet. This app calls VpnService to create the virtual network interface and modifying routing table. After this, the total packet will pass through this virtual network interface, and then capture the total packet that passes through this virtual network interface.
"iCap" used to analyze, filter and capture the specific network packet. According to the addition IoT app, "iCap" will analyze the user id of the addition IoT app, it use user id to verify the packet and capture packet from that IoT app directly. "iCap" also captures the specified packet which user can filter packet by input the packet Protocol, IP address, or Port number. Using this condition can help users to analyze network packets for specific targets, research of related protocols and detect the abnormal behavior of packets in the Smartphone.

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