# REISCH: Incorporating Lightweight and Reliable Algorithms into Healthcare Applications of WSNs
## 2 Related Existing Research  
This section briefly discusses existing studies [17; 18; 19; 20; 21; 22; 23; 24; 25] designed to secure patient data in the EMR and highlights their drawbacks.  
[PERSON] and [PERSON] [17] implemented ECDSA on Micaz motes with the binary field (163-bit). They improved signature verification via cooperation of the adjacent nodes. ECDSA's implementation was also presented in the sensor node (IRIS) [18]. However, because this node supported 8-bit of the microcontroller, the author modified the SHA1 code from the 32 bits original to 8 bits. Through implementation, the original algorithm is better in size and time than the modified algorithm. The author explained the possibility of using the ECDSA algorithm with the sensor node (IRIS) held 8-bit microcontroller.  
To store patient data accurately, data collection schemes should rely on reliable and fast hash algorithms in ECDSA. The authors of [19] applied the ECDSA algorithm as a lightweight authentication scheme in the WSN, demonstrating the effectiveness and efficiency of using ECDSA in WSN in terms of  
Figure 1: An attack on communication security (Intruder 1) and datasets security (Intruder 2).  
security and performance. [PERSON] et al. [20] designed an ECC/ECDSA-based scheme to provide privacy in WSN. However, they did not provide a performance analysis of the security algorithms during exchange of data in WSN. [PERSON] et al. [21] focused on the efficiency of transmission in WSN to extend the lifetime of sensor nodes with the use of ECDSA and generated message digest (MD) with data. Their scheme relied on a colony optimization scheme to save energy in the WSN. However, it did not support privacy parameters during data transfer. [PERSON] et al. [22] proposed a scheme to monitor the heterogeneous network environments in WSN and protect the medical information of patients using ECDSA. Unfortunately, their scheme addressed only the computation processes of transport. It did not address the complicated computation processes that generate and verify the signature in ECDSA.  
Recently, [PERSON] and [PERSON] [23] designed a data aggregation scheme that focused on computation in demand-response management to improve performance and security efficiency. Their scheme was based on the identity signature (Bilinear Map) to protect information and data aggregated by integration and authentication. [PERSON] et al. [24] proposed an elliptic curve cryptography (160 bits) scheme to encrypt and authenticate patients' biometric properties. They used wearable sensors to collect patient data and used a mobile device to send and store these data in the medical repository (cloud server). Finally, [PERSON] et al. [25] designed a framework based on RSA-2048 bits and trusted modules to secure the sensors' domain and prevent unauthorized threats. They organized sensors into master, replica, and gateway categories in the network area and data structure in the sensor memory. In their framework, security procedures for the domain and sensor were used to support both integrity and authentication. Moreover, many researchers [26; 27; 28; 29; 30] have pointed out that ECDSA is particularly appropriate for authentication and authorization schemes because it performs lightweight processes during security procedures. Many recent studies [31; 32; 33; 34; 35] have also pointed out that SHA1 suffers from collision, preimage, and second preimage attacks. However, no schemes addressed SHA1 performance and security (collision, preimage, and second preimage) problems in ECDSA.