# PiPatient Privacy Copyright Cloud Management
## 2 Related Work  
In this study, we used a symmetric key to encrypt and decrypt all transmitted medical record copyrights. Therefore, we established a secure tunnel for all transmitted data and designed a symmetric key agreement mechanism. The key agreement was roughly divided into two parts, namely offline processing and online processing. In the case of offline processing, the user had to use a token that was unavailable to others to initialize the key agreement. Prior studies used personal identity IDs and passwords for preliminary verification, which is often referred to as the two-factor verification method [1; 2]. When coupled with other auxiliary mechanisms or biological characteristics, they are often referred to as three-factor authentication [3; 4]. However, new research mostly used fuzzy hashing conducting one-way exclusive pairing for biological characteristics, changing slightly each time [5; 6]. Our research used fuzzy hashing plus identity anonymity; thus, it is a single-factor dynamic anonymous offline processing method [3; 4; 7]. Offline processing security vulnerability issues include smart card loss or brute force password cracking attacks, and many prior studies have also proposed possible vulnerabilities and solutions [8; 9; 10]. Alternatively, in the case of offline processing, a zero-knowledge information exchange key agreement was performed through the public network [11]. In the case of the key agreement mechanism, many scholars had proposed related agreements [8; 11; 12; 13; 14; 15]. In 2002, using fingerprints as passwords and using a remote login authentication through smart cards and biometrics were common [9]. Two years later, the improperly designed communication process posed a risk of masquerade attacks even though biometrics are hard to counterfeit [16]. In 2012, a study addressed a medical information system for an integrated electronic patient record (EPR) with a one-way operation hash function as the main security mechanism. The study also reduced the time of encryption and decryption operations through multiplications [17]. However, it was still possible to carry out impersonation attacks although prior studies provided irreversible  
Figure 1: iPatient privacy copyright cloud management system scenario map. encryption and decryption operations for medical information systems. Impersonators can obtain fake user information by hacking the database [12]. In the case of user anonymity, in 2017, some scholars addressed anonymous mechanisms [3; 4; 7; 14; 15]. However, our study found that the anonymity in many studies was pseudonymous because the same alias was also easily traced to an association with the real identity. Our study will design one real untraceable anonymous agreement. As telehealth has received substantially increased attention, cloud data communication and storage security for telehealth have become quite important issues [3; 18; 19; 20; 21; 22; 23]. There are many possible malicious attacks in traditional communication security issues such as man-in-the-middle, spoofing, and replay attacks [23; 24; 25; 26]. Recently, [PERSON] [27] proposed an authorized sharing mechanism for telehealth. Several weaknesses existed in [PERSON]'s scheme. [PERSON]'s scheme only discussed security protocols transferring data from the data centers to the hospital and lacked a design for storage or modification. Hospitals and data centers did not know the user's location and the real address, and consequently, they were unable to directly send communication messages. Additionally, the immutable pseudonyms were not truly anonymous and the medical record update did not establish a user-led secure channel, and data were probably at risk of being tampered with or counterfeited [27]. The main points of our study focus on the patients' complete anonymity but fully controlled through a zero-knowledge key agreement mechanism withstanding existing malicious communication attacks. All sensitive information is processed and transmitted after the secure tunnel is established.