Adaptive Contextual Token-Biometric Authentication (ACTBA) for Cloud Access: A Novel Two-Factor Security Mechanism

The rapid expansion of cloud computing has intensified concerns related to identity security and unauthorized access. Although two-factor authentication (2FA) mechanisms are widely adopted to mitigate risks associated with password compromise, many existing solutions rely on static authentication workflows that fail to adapt to dynamic threat conditions. Such rigidity often results in either weakened security or degraded user experience. To address these limitations, this paper proposes Adaptive Contextual Token-Biometric Authentication (ACTBA), a novel two-factor authentication framework specifically designed for secure cloud access. ACTBA integrates contextual risk assessment, time-synchronized cryptographic tokens, and lightweight biometric verification to dynamically adjust authentication strength based on real-time risk indicators. Formal definitions, mathematical modeling, and security analysis demonstrate that ACTBA provides enhanced resistance against phishing, replay, and credential theft attacks while preserving usability and user privacy. The proposed framework offers a scalable and future-ready authentication solution for modern cloud environments.