# Security Issues in IoT-Based Wireless Sensor Networks: Classifications and Solutions
## 3 Security Protection Schemes
### Secure Authentication Protocol Schemes  
A secure authentication protocol in WSNs focuses on identifying and verifying the identity of sensor nodes in the network to ensure data integrity and confidentiality. The SPIN protocol is a set of security mechanisms that ensure message authentication, data integrity, and confidentiality. SPIN is particularly suitable for operational decentralized sensor networks. To improve the SPIN protocol, [PERSON] [76] proposed a new authentication protocol RPT based on implementing the \(\mu\)TESLA protocol. It accepts urgent and infrequent authentications. However, RPT consumes more resources (computational capacity and energy storage) than the pTESLA protocol does. [PERSON] [76] proposed a second authentication protocol called LEA which uses asymmetric encryption. To be authenticated, the sending node creates a digital signature and sends it along with the data to the receiving node. The signature using the public key is decrypted by the receiving node and compared with the received data to confirm its validity. However, LEA has a size of signature proportional to the size of the message sent. Hence, it requires more storage space. Furthermore, LEA requires a unique public key for each message, forcing the receiving node to store a large number of public keys, leading to high computational cost.  
The TinySec protocol was proposed in the work of [PERSON] [77]. Two versions of the TinySec protocol are proposed without requiring high computational power: TinySec:Auth for authentication and TinySec-AE for encryption and authentication. The protocol is based on symmetric encryption and a 4-byte authentication code (MAC) mechanism which significantly reduces the security overhead. At the same time, by using a mechanism that allows a certain number of authentication attempts, the proposed protocol shows its effectiveness against MAC decryption attacks. The MiniSec protocol was developed by [PERSON] [78] from the SPIN protocol to provide a new authentication mechanism that consumes fewer resources than the Tinsel protocol. This solution is based on a new symmetric encryption algorithm (based on the block cipher OCB--Offset Code Book) with two authentication mechanisms, single authentication (MiniSec-U) and broadcast authentication (MiniSec-B). The simulation results show that MiniSec is more efficient in authentication and security. It also has lower energy costs compared to the TinySec-AE protocol.  
Furthermore, several secure authentication protocols were studied, such as the BASIS protocol with multi-user broadcast authentication mechanism based on ID proposed by [PERSON] [79]. The MBS-UAKA protocol was designed by [PERSON] [80] for efficient mutual authentication of WSNs with multiple base stations. [PERSON] [81] proposed an efficient two-factor ASKI-WSN mechanism based on ECC to overcome resource constraints and provide an acceptable level of security. The SUBBASE protocol introduced by [PERSON] [82] aims to authenticate based on the user's biometrics without using any password or additional hardware device.  
In WSN-IoT applications such as medical and military, where data is highly sensitive, authentication protocols are needed to protect against tampering and unauthorized access. Authentication protocols such as TinySec, MiniSec, LEA, RPT, and SUBBASE all focus on ensuring that only authorized entities can join the network and transmit/receive data. Protocols such as MiniSec are suitable for devices with limited resources (MiniSec uses lightweight AES encryption and compact MAC, saving energy and memory). Some protocols are resistant to eavesdropping and tampering attacks (LEA uses ephemeral key agreement mechanism). However, some authentication protocols only focus on authentication from node to sink or vice versa, while modern WSN-IoT applications require bidirectional and multi-point authentication.