Data Security in Microprocessor Units

Protection of computer systems from an unauthorized access to the classified information is a very essential issue. Security of IT systems can concern various aspects, such as software security, connected with ensuring its confidentiality, as well as preventing its modification. Thanks to the developed methods, it is possible to analyze the program code based on the disturbances of voltage supply, which occur during the execution of the program. Moreover, it also enables to recognize the numbers of bits changes on microcontroller data bus, as a result of realized instruction. In such context, it can constitute a potential threat for data processed by microcontroller program or embedded systems. The presented method is very similar to simple power analysis method, which is very effective in relation to cryptographic algorithms, whose execution in many cases depends on processed data. The results indicate that presented method is an effective and low-cost attack, due to its simplicity in many real applications. Moreover, the research results inspire to study carefully the ways and methodology for developing software and hardware, which should reduce the possibility of software reverse engineering.