Study On Broadcast Encryption And Key Pre-distribution Schemes

In the open distribution networks, the issues of information security become more and more serious. One of the most popular and practical methods to ensure the security of the transmitted datum in the open networks is to encrypt and authenticate it. The encryption algorithm is always assumed public to the attackers in the modern cryptology. The information security depends on the key's security entirely. There are many user groups in the open networks, which the member join and revocation is a grimness challenge. So, how to establish a perfect group's key management system is fundamental for solving the issues of information security, which can ensure that not only users add or revoke at any time, but also forward security and backward security, furthermore, we hope the overheads of whole management system is the lowest. This is just one of the research topics of cryptography and information security.This thesis mainly focuses on the key distribution, which is one of the most important aspects of the key management. We study on broadcast encryption and key pre-distribution schemes.(1) In the key distribution scheme, we mend a new randomized Broadcast encryption scheme. The new scheme can securely distribute keys, and each user storages (l + 1) keys only, which can ensure that powered user find decryption key at rate of 1, and can reduce transmission cost to minimum under some condtion. (2) In the key distribution scheme, we present an one-way key sequence distribution scheme based on RKPS(Random Key Pre-distributio Scheme) and BES(Broadcast Encryption Scheme). The RKPS, Due to the inherent advantages of low resource consumption and computation is suitable for wireless sensornetworks. The scheme guarantees a high connectivity, reduces node computations,transmission cost and the rate of invalid chain among nodes greatly.(3) In the key distribution scheme, we present a secure session key distribution scheme based on broadcast encryption. The scheme reduces the key storage requirement of GC to a constant size O(1), which is far better than that of the previous proposed schemes and can securely distribute key, add new users and renew encryption-keys successfully, furthermore, the scheme can be easily extended to secure many-to-tmany group communications.(4) In the protocol of the member join, we cite a preserved node scheme, which ensure that the original member key remain the same after the fresh member joins into the group, and the encryption key can renew automatically.(5) In sensor networks, we proposes a key pre-distribution and dynamic distribution scheme based on deployment knowledge of the sensors that constructs a key management tree to achieve communication security. It is a new key pre-distribution mode in wireless sensor networks. We make use of information pre-loaded in nodes to guarantee a high connectivity and security and a low energy consumption. Our scheme employs the distribute and integrated key management, it is suitable for large-scale sensor networks.