Automata theory is dominating in many applications developed from the concept of finite state machine (FSM). This research will consider the design of vending machine (VM), which improves the books delivery service in the academic institution, illustrated by an application. An efficiency of VM is considered as a problem. In order to improve the efficiency, automata theory depends on the design of the FSM and visual automata simulator (VAS) are used as a method. Finally, the paper will construct FSM that uses fewer states. As a result, we will find that we can improve the efficiency and design cost of the VM. General TermsAutomata theory and FSM are considered as our general terms. Throughout this research, VAS is also considered for graphical representation.

Currently, the major problem for software developers is software piracy. To protect software from piracy, many techniques are developed, and one of them is software watermark. Software watermark provides authentication and copyright protection by embedding a watermark into the software, and the owner can claim ownership of the software by watermark extraction. The software watermarking improves the computer security with a robust solution to expose the unauthorized modification or illegal copying of different kind of attacks. Now, there many techniques for embedding and extracting watermark into software and most recent one used malicious code like return-oriented programming (ROP) for good uses. Moreover, any software protection with an efficient watermarking algorithm based on ROP is a relatively new branch of computer security. Thus, in this paper, new software watermark has been designed using ROP technique that enhances the existing one. The watermark has been embeded using ROP and it has been extracted once ROP trigger is triggered. ROP trigger uses a SHA256 hash function to compare between watermark secret input and user entered key. As a result, the proposed work has strong resilience, Stealth and minimum runtime overhead.

Applications of computer security issues are limited to the operating systems and gadgets used within the computers and all other devices integrated with supercomputers. With the growing number of users, software developers face the software piracy which could affect the computer systems. Currently, the major problem for computers in the different industries is software piracy. Despite many computer security techniques, we have proposed a software watermark design based on return-oriented programming (ROP). Here, the new design of the software watermark is considered as a method in which secure Hash algorithm plays an important role to enhance the performance of the computer security. In this method, we focused on gadgets analysis gadgets categories and a large number of gadgets. In this analysis, we selected Sjeng benchmark and ROP with different approaches. As a theoretical result, resilience and stealthy are compared with existing results. This approach can be useful to improve the application of the computer security laws with legal procedures depended on the proposed computer security algorithms and analysis.