Conclusion
Whereas the potential opportunities ofered for big data in the healthcare arena are unlimited (e.g. drive health research, knowledge discovery, clinical care, and personal health management), there are several obstacles that impede its true potential, including technical challenges, privacy and security issues and skilled talent. Big data security and privacy are considered huge obstacles for researchers in this feld. In this paper, we have briefy discussed some successful related work across the world. We have also presented privacy and security issues in each phase of big data lifecycle along with the advantages and faws of existing technologies in the context of big healthcare data privacy and security. We mainly reviewed the privacy preservation methods that have been used recently in healthcare and discussed how encryption and anonymization methods have been used for health care data protection as well as presented their limitations. Additionally, there are more various techniques include hiding a needle in a haystack [61], Attribute based encryption Access control, Homomorphic encryption, Storage path encryption and so on. However, the problem is always imposed. In this context, as our future direction, perspectives consist in achieving efective solutions in privacy and security in the era of big healthcare data. As well, privacy methods need to be enhanced. Also with the rapid development of IoT, the greater the quantity, the lower the quality. Consequently, quality of data should not be afected more by privacy preserving algorithms to get the appropriate result by researchers. And to go further, we will try.