In this paper, we consider Homomorphic Encryption (HE) to process over encrypted data in order to achieve user privacy. We present a framework solution to provide a high level of security for the symmetric HE algorithms. The proposed solution introduces a dynamic structure and dynamic diffusion's primitives that enhance existing symmetric HE algorithms and overcome their weaknesses. We apply this solution to a well known symmetric homomorphic approach, the PORE (Polynomial Operation for

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... ation and Encryption) approach. The security analysis of the proposed solution shows that it ensures a high level of security without performance degradation. It is also evaluated against different attacks. This leads to secure and efficient HE Algorithms for practical implementations.