Research On The Broadcast Encryption Scheme And Its Applications

With the rapid development of multimedia and Internet, most data suppliers send their internet service through the radio. In order to protect the rights of authorized users, data suppliers need to prevent unauthorized users get the provided services. Broadcast encryption provides an easy way to make legitimate users to receive the useful information that distributed through unsecure broadcast channels. In addition, another problem that data suppliers need to deal with is piracy. If an authorized user(traitor) provides his decryption key to unauthorized users, or some authorized users seek to construct new decryption key and provide the key to unauthorized users, so that unauthorized users can also receive the services provided. Now most data suppliers use traitor tracing technology to track the traitor when they find piracy, and then give them some punishment accordingly.In this paper, we make specific research on broadcast encryption and traitor tracing, and the research results are as follows:(1) We first analyse a asymmetric broadcast encryption scheme based on the discrete logarithm problem, pointing out the existence of security vulnerabilityes of the scheme, and a new broadcast encryption scheme based on secret sharing was proposed. The new scheme using secret sharing in another way, which reduces the amount of decryption computation by pre-reconstruct the interpolation share. Analysis shows that the new scheme can remove and add subscribers securely without the subscribers to change their decryption keys.(2) We first analyse a traitor tracing scheme based on bilinear mapping, pointing out that the scheme can not remove any subscriber in the revocation of the scheme, and improve the scheme, a new traitor tracing scheme based on bilinear mapping was proposed. In order to achieve the purpose of revocation, the new scheme publishes the interpolation share of the removed users, insure that the removed users can not reconstruct the session key. The new scheme can also meet the full collusion,black box tracking,complete withdrawal,complete recoverability.(3) We design a P2P audio playback system based on the broadcast encryption scheme proposed by this paper, and implement the system using VC++ 6.0 in windows XP environment.