Evaluate the security challenges posed by Single Page Applications (SPAs) compared to traditional web applications.

SPAs present unique security challenges including increased client-side attack surface, complex authentication flows, and sensitive data exposure in browser memory. Traditional server-side validation becomes more critical as client-side controls can be bypassed. SPAs require robust token management, secure API design, and careful handling of sensitive data. However, they also offer benefits like reduced server-side attack surface and better separation of concerns when properly implemented with security-first design principles.