Research And Implementation Of Enhanced Sip-based Voip Confidentiality

VoIP have gone into domestic for more than 10 years. It obtains authorization for the advantages, such as cheapness and convenience. However, for the usability and flexibility, SIP adopts the text mode similar to HTTP, which possesses the characteristic of sending clear message. So privacy is its weakness. So there are full of detection, eavesdropping, attacks,, interference, restriction and destruction against VoIP emerge in endlessly and affect the call quality to a large extent.The paper analyzed and studied the clear message transmission of SIP-based VoIP based on the analysis utility wireshark, implementation utility Boraland C++ Builder and the goal of improving privacy of VoIP, put forward a solution of packet transform to enforce the privacy of VoIP in order to reduce t various damage. The work of the paper included the following:1. Based on the principle of VoIP and the relevant research at home and abroad, the paper analyzed the various security mechanism, proposed a solution to enforce the privacy of VoIP based on packet transform. The method of packet transform can not only meet the confidentiality requirements but also hide the protocol information. So it protects the privacy of message, effectively avoid eavesdropping and destruction. And it has the advantage of implementation simplicity, as well.2. According to the requirements of packet transform the paper studied the implementation means of packets interception and proposed the way of using intermediate driver. First, filtering in the driver level has advantages of without having to pack, rapidness and efficiency. Second, all the data diagram via physical network cards can be intercepted, so to avoid the shortcoming that the data diagram can't all be intercepted at the user level. Moreover, interception based on drive level takes on the virtues of mature technology, high reliability and has the ready-made modules for the program calls. So it is implemented simply.3. Based on previous work, the paper put forward processing means of packet transform and inverse transform based on C/S framework for characteristics of pacjet transform and the requirements of transmission. C/S framework arranges the task of packet transform and inverse transform to the client and server reasonably and satisfies the requirements of transmission of cipher-text by Internet.The experiments confirmed that privacy is enhanced and communication quality is guaranteed after VoIP is processed by the previous method.The implementation of the paper is to enforce the privacy of SIP-based VoIP. However, the treatment is for IP address, not for the specific protocol. So the implementation of the paper does nothing with protocols and effectively enforces the privacy of VoIP based on other protocols.