# REISCH: Incorporating Lightweight and Reliable Algorithms into Healthcare Applications of WSNs
## 4 BLAKE family
The extensible access control (XML) is considered convenient for the exchange of various data via different environments. XML is the symbolic, simple, and flexible language designed to manage, describe, and exchange data across the Internet. It divides the data into the form of useful information through data organization, for the purpose of sharing data across different systems and storing them in the dataset. Moreover, XML has several features that make it suitable for data management, such as support for unicode, the representation of computer data structures (trees, records, and lists), and using a formula read by both humans and computer. However, XML should support the security mechanisms to provide different levels of protection of sensitive data in the whole or part of the XML document [66]. Access to the data is a challenge in big data management systems that use different techniques. In addition, the exchange of information over an insecure environment has become essential, particularly in HC applications. However, this information needs mechanisms to identify the arrival of unauthorized users to protect patient data. Patient data transmitted between sensors (nodes and \(CH\)s) and network devices (such as a nurse and a \(LS\) device) need data management algorithms to maintain both performance and security at the same time. EMR including patients' confidential data and private information needs to be accessed by HC professionals. Thus, sharing such EMR without breaching a patient's privacy requires EMR management in an efficient and secure manner. XML technology has begun showing its superiority in the exchanging of complex data over different systems. * **Homomorphic scheme*
* A homomorphic is a mechanism for merging all messages and signatures together to improve both performance efficiency and security. This mechanism consists of many types such as linear, polynomial, full, and aggregate signature [67]. In this study, we focus on the aggregate signature because it deals with multi-sensors signatures, messages, and different private keys depending on different devices such as sensors. Furthermore, this process is extremely suitable for multihop-based networks during the integration of signatures into a single signature. We assume that we have a range of messages \(M=\{m_{1},\ldots,m_{n}\}\) and a range of signatures \(S=\{s_{1},\ldots,s_{n}\}\), \(M\) contains all group's messages together, where \(S\) is one signature for all signatures, \(A\) is an aggregate function, and \(V\) is a verification function. The process of homomorphic signatures is as follows:
* Each device generates \(K_{pr}\) and \(K_{pu}\) keys and broadcasts the \(K_{pu}\) keys to network members. * Each device signs the \(m\) by the signature algorithm, which includes the device's ID, message and private key \(s(K_{pr},m_{i},ID)\). * The aggregation procedure in the intermediate nodes such as \(CH\) relies on \(A\) to collect all public keys, messages and signatures \(A(K_{pu_{1}},\ldots,K_{pu_{n}};m_{1},\ldots,m_{n};s_{1},\ldots s_{n})\). * The verification procedure will be in the final entity such as \(LS\), which uses \(V\) to validate the signatures \(V(K_{pu_{1}},\ldots,K_{pu_{n}};m_{1},\ldots,m_{n};s_{1},\ldots s_{n})\). If the verification process fails, it means that the data integrity operation is incorrect. The homomorphic aggregate signature scheme is important to support the performance of network devices by making the intermediate nodes such as \(CH\) perform a single signature process for all members' signatures of the group rather than the signature verification process (the ECDSA verification process consumes more time and energy than the signature process) [68]. In addition, homomorphic increases security measures in preventing the tracking of patients' information and data or changing signatures of legitimate network devices [69].