Improvement Of AKA Protocol And Design Of Cryptography Algorithm In 3G

With the unceasing development of the universal communication technique. it will be anundoubted result that the communicating system in our country develops from 2G to 3G. Sincethe internal use of commercial ciphers is rigorous restricted by the Chinese government, it doesnot fit in with the practical environment to directly copy the 3GPP standard to our country.Hence it is of great importance for our country to independently design the cryptographyprotocols according to 3G security requirements.In the dissertation an analysis is given on the security, whose improvments take up the workin the dossertation. In authentication and key agreement, an improvement is made to AKAprotocol. While in communication data confidentiality and integrity, a stream cipher TAIYI isdesigned according to 3G requirements. The detailed work is as follows:An investigating is made on the course of AKA protocol and the improvements in theexisting literatures, whose merits and shortcomings are analyzed whereafter. Through theseanalysis a new improved AKA protocol is put forward, which is compared later with the previousimprovements in both security and efficiency. On security, comparisons are made based on keysharing refreshing, unprotected key transmitting, full authentication, etc. On efficiency theaspects being taken into consideration are communicating times, computational cost, etc.An analysis is given on how f8 and f9 work based on KASUMI. According to their framesin 3G standard, the cipher TAIYI is designed, which is a stream cipher based onσ-linearfeedback shift registers. Both software and hardware implementations of TAIYI are taken intoaccount in the dissertation. The security of TAIYI is also analyzed in the following part, wherethe content is about the properties of theσ-LFSR, the cipher security against time-memory-datatrade-off attack, correlation attack, algebraic attack and distinguishing attack, together with itsMAC security. Furthermore 12 kinds of tests of randomness are made, with their results tabledbehind.