# Cryptographic Protocol with Keyless Sensors Authentication for WBAN in Healthcare Applications
## 2 Related Work
This protocol has 5 phases, and the results indicate that the protocol is secure in certain scenarios but also obtain an inconclusive result, which, according to the tool manual, does not imply that an attack has been detected. In 2019, an authentication protocol [18] for TMIS use was introduced based on the protocol developed by [PERSON] et al. [19]. The authors analyzed the security of the protocol using protocol verification tools, starting with AVISPA [17], in which two of the scenarios provided by the tool were analyzed. Similarly, the protocol is verified using the Scyther tool [20,21]. The proposed protocol is developed with four main entities: (1) Medical Record Server (MRS), (2) Medical Server (MS), (3) Patient Server (PS), and (4) Patient Unit (PU). If a server is controlled directly by a doctor, then it is a PS; otherwise, it is an MS. The protocol works with one server at a time. The proposed revised protocol contains 9 phases, unlike the 6 phases in the one by [PERSON]. The verification results with AVISPA indicate that the protocol is safe against some attacks that the tool verifies. The results of Scyther show that the principal values used to generate keys in different phases remain secret, and in the same way, the entities remain authenticated. Therefore, the protocol provides authentication of the entities, confidentiality, and integrity to the data handled. In 2020, the work in [22] was presented, in which the authors propose a protocol for IMD. The protocol is functional, does not risk the life of the patient who uses it, and was evaluated for protection against denial-of-service attacks. The protocol was subjected to safety tests using the AVISPA tool [17]. If the attacker has complete control of the communication channel, the system can be analyzed to determine if it meets certain security requirements. The environment in which the protocol is developed considers four entities:(1) Smart card (C) for the user (U), (2) Hospital server (S), (3) Implant (I), and (4) Reader (R). Entities C and S provide the protocol with security services: non-repudiation, access control, and user authentication. This protocol has 4 phases to provide the services of confidentiality, integrity, non-repudiation, access control, and user authentication. The protocol has two ways of working. The first one considers that all entities have an internet connection. When this is not possible, the protocol enters the second model, which proposes the exchange of keys between only three entities, preventing the server from being the one that sent the keys. Vulnerabilities against man-in-the-middle and, repetition attacks are sought. The analysis yielded results by phase, showing that some phases do not comply with all security services. In 2020, work at [23] presented an efficient privacy-preserving protocol with anonymous authentication to provide information security and privacy to users with low computational and communication costs. The protocol maintains communication between a network manager, sensors placed on the patient's body, a controller device, and a medical server. Communication is done in three main phases: (1) System initialization. (2) Registration of sensors. (3) anonymous authentication between patient to doctor and doctor to patient. One of the characteristics of this protocol is that the records are made personally between the patient and the doctor with the network manager. The protocol guarantees the security services of confidentiality, authentication, and integrity. The protocol is analyzed in three ways: (1) informal security analysis, (2) formal security analysis based on BAN logic, and (3) formal security analysis using the AVISPA [17] tool. The results of applying AVISPA and the informal analysis show that the protocol is safe and even ensures it is safer against impersonation attacks. In 2020, the work in [24] presented a key agreement and authentication protocol based on hash and XOR functions.