Change of cloud computing to federated ecosystems has come with complicated issues connected with entry control, setting, and checking of policies, and well-being. The traditional role-based access control (RBAC) and centralized attribute-based access control (ABAC) machinery are limited and not risk-free to internal risks, single-point failures, and audit trails manipulation and do not perform well with dynamic and cross-domain access demands. In abating these cybersecurity issues, a Blockchain Driven Access Control and Compliance Auditing Framework is proposed in this paper and tailored towards federated cloud service providers. Unlike the current approaches to blockchain-based ABAC, this framework marries blockchain technology and decentralized ABAC to provide tamper-resistant policy management, real-time compliance checking, and accountability of access. The use of smart contracts allows enforcing the access conditions to be autonomous and to log all the access transactions on the blockchain ledger in an immutable manner, and as such, this improves the data integrity, traceability, and non-repudiation. The target is privacy-informed decision-making and is achieved through a cryptographic token mechanism, which enables secure policy referencing without disclosing any sensitive attributes. Using thorough experimental simulations, it is proved that the suggested model gets the outstanding compliance violation detection rate of 96.4% which is vastly greater in disparity to traditional RBAC (83.1%) and centralized ABAC (87.5%) models. Additionally, the system enhances policy verification time by 35.2% and lowers average access latency by 28.7%, which proves that the system is efficient in high-load conditions. The blockchain module can effectively support an average of 52.3 transactions per second (TPS) with the average node resource consumption rate staying at less than 68%, which proves its scalability and sustainability of its work. The framework proposed is a comprehensive cybersecurity solution that would enable the implementation of trust-less access governance, autonomous audit logging, and strong security controls to ensure the cybersecurity of cloud federations. It potently re-minimizes attack areas, is audit-friendly and permits safe inter-provider cooperation as a noteworthy stride to sturdy and decentralized cloud infrastructure, plus policy-driven cloud infrastructures.