Enhancing Secure Cloud Storage: A Four-Tier Architecture with ChaCha20 Encryption, Blake3 Hashing, and Dynamic Chunk Allocation in Multi-Cloud Environment

With the growing reliance on cloud computing for storing and managing data, providing security and performance for cloud storage systems has become very important and multicloud solutions offers both. Current cloud architectures suffer from scalability, security, and efficiency issues in distributed cloud systems. In this paper, we introduce a ChaCha20-encryption, a fast stream cipher and Blake3, an adaptive cryptographic hash function, and dynamic chunk allocation to an existing architecture that progressively improves data confidentiality, integrity, and redundancy. The experiment focuses on the system's performance relative to Four Tier Secure Cloud Storage Architecture, which utilizes AES, MD5 hashing, and static chunk allocation strategies for data storage. To ensure a balance between performance while offering the security this architecture implements ChaCha20 which is fast and resistant to side-channel attack – making it ideal for modern multi cloud deployments. Experiments show that this new architecture is faster, more lightweight and adaptable than existing model.