Data security and sharing remains nuisance among many applications like business data, medical data, banking data etc. In this research, block chain technology is built with encryption algorithm for high level data security in cloud storage. Medical data security seems critical aspect due to sensitivity of patient information. Unauthorized access of medical data creates major issue to patients. This article proposed block chain with hybrid encryption technique for securing medical data stored in block chain model at cloud storage. New Two fish encryption model is implemented based on RSA Multiple Precision Arithmetic. MPA works by using library concept. The objective of using this methodology is to enhance security performance with less execution time. Patient data is processed by encryption algorithm and stored at blockchain infrastructure using encrypted key. Access permission allows user to read or write the medical data attached in block chain framework. The performance of traditional cryptographic techniques is very less in providing security infrastructure.

翻译：数据安全与共享在许多应用领域（如商业数据、医疗数据、银行数据等）中仍是一个棘手问题。本研究将区块链技术与加密算法相结合，以实现云存储中的高级别数据安全。由于患者信息的敏感性，医疗数据安全成为关键环节。未经授权的医疗数据访问会给患者带来重大问题。本文提出了一种结合混合加密技术的区块链模型，用于保护云存储中存储在区块链模型中的医疗数据。基于RSA多精度算术（MPA）实现了新型双鱼加密模型，MPA通过使用库概念进行运算。采用该方法的目标是在减少执行时间的同时提升安全性能。患者数据通过加密算法处理后，利用加密密钥存储在区块链基础设施中。访问权限允许用户读取或写入区块链框架中附带的医疗数据。传统密码学技术在提供安全基础设施方面的性能非常有限。