CRYPTOGRAPHIC FOUNDATIONS OF CLOUD SECURITY: A SURVEY ON TRUST MODELS AND ZERO-KNOWLEDGE PROOF-BASED AUTHENTICATION

Abstract

Cloud data storage helps people keep huge amounts of data on demand and for a low price. However, ensuring users
can access the data safely and privately remains a significant challenge. Existing solutions to the problem of data privacy using
cryptographic role-based access control (RBAC) systems often suffer from issues such significant computational overhead,
reliance on trust, and inability to guarantee fair authorization and safe data retrieval. This study introduces a paradigm for trustenhanced
access control that integrates blockchain with searchable attributes-based encryption. It offers decentralized, transparent,
and tamper-resistant access management, which is a solution to these problems. Furthermore, to improve decision-making in realtime,
offer a data-oriented risk-based access control model that integrates dynamic risk assessment across subject, resource, and
environmental factors. investigate new cryptographic trust models (such as blockchain, web-of-trust, and Zero-Knowledge Proofs,
or ZKPs) and other emerging technologies to see whether they can provide safe authentication without revealing secret credentials.
Cloud access gateways are proposed to localize trust and reduce reliance on vulnerable centralized architectures. Also, examine
the limitations of current Access Control as a Service (ACaaS) and PKI-based authentication solutions. Finally, present a
blockchain-based framework that combines smart contracts, distributed ledgers, and cryptographic protocols to ensure
decentralized access control, privacy preservation, and auditability. It clouds service providers to deploy scalable, secure, and
privacy-respecting systems, fostering broader adoption in sensitive application domains.