Industrial Automatic Control Systems and Controllers Annotation << Back The Application of a Risk-Based Approach to the Study of the Reliability of Authentication Algorithms Ermakova A.Yu. The article examines the effectiveness of authentication algorithms used to protect information systems from unauthorized access in the form of a username and password. At the same time, both the entrance to the information system itself and the entrance to a separate directory inside the system can be protected. Many works have been devoted to the reliability of password systems and the formation of passwords themselves, such as the choice of the alphabet from which they are selected, their length, frequency of change, and other similar issues, both in popular science literature and in textbooks on the basics of information security [2, 3]. At the same time, the recommendations for basic parameters, such as the length of the password, vary greatly and range from 6 to 25 characters, and the replacement time ranges from one day to several months. In this paper, based on the application of a risk-based approach and forecasting the development of computer technology, estimates of the timing of the secure use of passwords are obtained depending on their length and the power of the alphabet from which they are selected. These estimates were obtained under the assumption that password characters are selected independently of each other according to the urn scheme with the return of a set of alphabet characters. Calculations of the time for determining the true password option have been performed without taking into account the increase in computer hardware performance and taking it into account. It is shown that when the password is 10 characters long in an alphabet of 64 characters, the time to fi nd the password is signifi cantly reduced, taking into account the increase in the speed of calculations. Keywords: risk-based approach, authentication algorithms, password systems, forecasting methods, approximating functions. DOI: 10.25791/asu.5.2025.1585 Pp. 24-31.