Abstract : Homomorphic encryption stands out from other encryption techniques by enabling arbitrary computations on encrypted data without revealing the original plaintext. Re- searchers have extensively studied various encryption methods, highlighting the importance and efficiency of homomorphic encryption in data security. Its deployment in the financial sector is crucial for ensuring the safe utilization of the vast financial transaction data in open banking. While there have been studies on partial (PHE), somewhat homomorphic encryption (SHE), and fully homomorphic encryption (FHE), they haven't specifically investigated its application within open banking platforms utilizing big data sharing. This study tested a fully homomorphic encryption algorithm on an open banking dataset, using an open-source Linux database and the SEAL homomorphic encryption library. The study explores the application of fully homomorphic encryption algorithms in se- curing financial data. The practical deployment demonstrates its effectiveness in ensuring data security, even in the event of a breach. Additionally, the study's results hold im- plications for the future development of open banking and big data sharing technologies, emphasizing the importance of advanced encryption methods for maintaining data privacy and integrity.