Analysis and Modification of Grain - 128 Stream Cipher Algorithm

This thesis presents a new stream cipher algorithm. The new cipher algorithm have been proposed based on the existing Grain - 128 stream cipher algorithm. There are three main objectives in order to achieve this purpose. The first objective of this research is to identify the randomness of Grain - 128 of stream cipher algorithm. Next, the modification of the algorithm will be conducted against Grain - 128 stream cipher algorithm. Finally, the randomness testing of Modified Grain - 128 of stream cipher algorithm is conducted to determine whether this algorithm is random or not random. The comparison of Grain - 128 and Modified Grain - 128 will be evaluated by using NIST Statistical Test Suite. The NIST Statistical Test Suite was developed by collaboration between the Computer Security Division and the Statistical Engineering Division at National Institute of Standard and Technology (NIST). The NIST Statistical Test Suite is conducted to determine the randomness of both algorithms. Conclusively, the Modified Grain - 128 is random based on 1% - 5% of significance level compared to the Grain - 128 which is not random at the same significance level.