Towards the Uses of Blockchain in Mobile Health Services and Applications: A Survey <s> M-Health Blockchain System: A Conceptual Proposal <s> A health-care system gathers comprehensive physiological information and medical records, making its data more important than ever. For example, for years now, the National Health Insurance Administration (https://www.nhi.gov.tw/English/) of Taiwan has requested every doctor, whether in a medical center or private clinic, to upload the diagnosis result, treatment, and prescription. These anamneses have also been stored in the National Health Insurance Research Database (http://nhird.nhri.org.tw/en/index.html) since 1 March 1995, and 99.9% of the Taiwanese population have been enrolled since 2014. With this comprehensive database, analytics tools can be run to uncover useful information to further understand the etiological factors for rare disorders. This database is successful primarily because Taiwan is a small but densely populated island, making it relatively easy for the government to collect most, if not all, the anamneses. <s> BIB001 </s> Towards the Uses of Blockchain in Mobile Health Services and Applications: A Survey <s> M-Health Blockchain System: A Conceptual Proposal <s> Healthcare is a big application scenario of blockchain, and blockchains used in healthcare are called health blockchain. In general, blockchain blocks are open and the transactions in them are public. If some privacy data are involved in these transactions, they will be leaked. Owing to healthcare system involving a great deal of privacy data, certain security mechanisms must be built to protect these privacy data in health blockchain. Furthermore, because the core of security mechanisms is the key management schemes, the appropriate key management schemes should be designed before blockchains can be used in healthcare system. Here, according to the features of health blockchain, the authors use a body sensor network to design a lightweight backup and efficient recovery scheme for keys of health blockchain. The authors’ analyses show that the scheme has high security and performance, and it can be used to protect privacy messages on health blockchain effectively and to promote the application of health blockchain. <s> BIB002 </s> Towards the Uses of Blockchain in Mobile Health Services and Applications: A Survey <s> M-Health Blockchain System: A Conceptual Proposal <s> Electronic Health Records (EHRs) are entirely controlled by hospitals instead of patients, which complicates seeking medical advices from different hospitals. Patients face a critical need to focus on the details of their own healthcare and restore management of their own medical data. The rapid development of blockchain technology promotes population healthcare, including medical records as well as patient-related data. This technology provides patients with comprehensive, immutable records, and access to EHRs free from service providers and treatment websites. In this paper, to guarantee the validity of EHRs encapsulated in blockchain, we present an attribute-based signature scheme with multiple authorities, in which a patient endorses a message according to the attribute while disclosing no information other than the evidence that he has attested to it. Furthermore, there are multiple authorities without a trusted single or central one to generate and distribute public/private keys of the patient, which avoids the escrow problem and conforms to the mode of distributed data storage in the blockchain. By sharing the secret pseudorandom function seeds among authorities, this protocol resists collusion attack out of $N$ from $N-1$ corrupted authorities. Under the assumption of the computational bilinear Diffie-Hellman, we also formally demonstrate that, in terms of the unforgeability and perfect privacy of the attribute-signer, this attribute-based signature scheme is secure in the random oracle model. The comparison shows the efficiency and properties between the proposed method and methods proposed in other studies. <s> BIB003
Following the advantages and challenges mentioned previously, a m-Health blockchain system can be implemented exploiting the advantages and neutralizing some of the major issues. The four main concerns are in patient data ownership, access control of patient healthcare information, the increase of interoperability between different health service providers and the ability to use patient data for research purposes without it ever being linked to a patient. As such, in terms of concept, the system would behave much like what it would now, with a few notable exceptions: 1) A blockchain would be created to serve as an access record. When a user accesses a patient's health data, this information would be added to a block and later recorded into a blockchain available to said patient; 2) In the previously mentioned blockchain should be a field with information regarding the state of the information present, such as an cryptographic hash of the information regarding the patient; 3) Patients should have the ability of, through a mobile application, access both their health data and the access records of said data; 4) All of the above points should be integrated onto existing systems using open standards and technologies. The architectural implementation of such a system is approximate to what can be seen in figure 3 . Regarding the aforementioned system concept, the biggest contributions come from the ability to greatly enhance the control and ownership capabilities of health data by the patients. Having privacy measures that they can trust in, that they can access and conclude on their efficacy and reliability, whereas previously the data would be stored in closed locations that the user could not access and, even if this still holds true, all access to the data is recorded into an open blockchain. Obviously, the information present in a public blockchain is completely open, so privacy has to be considered by adding encryption and other mechanisms so that privacy of this data is established. Several proposals have risen that handle this issue, such as  , BIB001 , BIB002 , BIB003 . In cases where there is no direct control of the data by the patient, he can still clearly see who accesses it, due to the blockchain being openly available, which increases auditability and, therefore, trust in the system. With this kind of blockchain access integration, medical history could also be closely monitored for changes and, depending on the kind of implementation, either a sign of change or detailed change records could be achieved. By having a m-Health application on which patients can rely upon to access their health data and to see who accessed their data empowers them to have a clear idea of possible privacy leaks and act upon this information, taking advantage of the immutability of the access records.