Software security is paramount in today's digital landscape, especially where sensitive information and functionalities are increasingly accessed online. Traditional single-factor authentication, relying solely on passwords, is susceptible to breaches due to weak password practices and phishing attacks. This paper explores the design and implementation of a two-factor authentication (2FA) model as a robust security measure to strengthen software applications. It emphasizes the enhanced security provided by 2FA, requiring possession of both a "something you know" (password) and a "something you have" (secondary factor) for successful login. This study delves into the design aspects of the 2FA model, considering various secondary factor options. Common implementations like SMS-based one-time passwords (OTPs), authenticator apps generating time-based OTPs, and hardware tokens are discussed. The selection of an appropriate secondary factor depends on factors like usability, cost-effectiveness, and desired security level. The paper acknowledges potential challenges associated with 2FA, such as user adoption, potential inconvenience, dependence on external factors like phone connectivity, Man-in-The-Middle Attack (MTMA). By adding an extra layer of verification, it significantly reduces the risk of unauthorized access, protects sensitive data, and fosters trust among users. The paper emphasizes the importance of user education on strong password practices and secure handling of secondary factors to maximize the effectiveness of the 2FA system., and concludes by emphasizing the importance of 2FA as a critical security measure for software applications and the positive impact it has on user trust and data protection.

Keywords: Security, Authentication, Two-factor Authentication, Cyber-attack.