# A Survey on Consensus Protocols and Attacks on Blockchain Technology
## 10 Discussion  
Blockchain technology is the most popular technology adopted by many industries, and many sectors are working on implementing this technology [96; 99]. This technology has many benefits that are very useful in data security and decentralization. Some core benefits are as follows:  
* Real-time transaction settlement
* More security and transparency
* No third-party involvement
* Durability and reliability
* Immutability
* Cost saving
* User pseudonymity  
In [100], [PERSON], [PERSON] et al. discussed how studying social networks can affect many aspects of life and also help many businesses in some cases. Given the relevance of the two concerns of social networks and R&D, their study investigates the relationship between social networks, technology relationships, and information security efficiency with the performance of research and development projects at the MAPNA development company. For this case study, they distributed a questionnaire of 19 questions to 196 employees of the company, and after receiving the results they found that social networks have a positive impact on research and development performance and information technology. In [101], [PERSON] et al. discussed this idea in a research and technology organization by investigating it from two perspectives: \"the notion of effectiveness in research projects\" and \"the concept of effectiveness in RTOs\" (RIPI). At the Research Institute of Petroleum Industry, eight technology development projects are being studied in order to evaluate and implement the recommended framework. The effectiveness of eight technology development projects was evaluated using ARAS, COPRAS, MOORA, and TOPSIS multi-criteria decision-making approaches based on the specified indicators and their weights. This paper discussed the consensus protocols and attacks on blockchain technology. The consensus protocols and attacks on blockchain technology are presented in detail in this study [52; 102]. The ECDSA (elliptic curve digital signature algorithm) is used in many blockchain-based architectures for security consideration, but still many threads are attacking blockchain-based architectures. As a result, we have discussed the consensus protocols and classifications of attacks for research purposes. In the near future, many sectors will use this technology for better security and privacy, so our focus is to enhance the security and efficiency of blockchain [103; 104; 105; 106]. This paper will guide other researchers to identify the privacy and security gaps in blockchain technology. In Table 5 we have mentioned some existing surveys and their outcomes. In previous surveys, we found that most of them used popular consensus protocols and attacks, but now there are many consensus protocols proposed and they have to be reviewed for further enhancement of blockchain technology [107; 108]. Three are also many attacks happping in blockchain technology that need to be reviewed. In this survey article we tried to provide researchers with detailed information regarding all 30 consensus protocols. By analyzing this paper, they can implement new ideas to enhance the security features of blockchain. As this technology is not limited to cryptocurrency, many other sectors such as education, healthcare, government, etc., are adopting this for securing their records. Due to the distinctive characteristics of blockchain, it may be applied in a variety of fields, such as IoT networks, healthcare, data storage, inventory monitoring, and finance [77]. The main problem is figuring out how to tailor blockchain technology to specific application requirements. As each application has unique requirements, a new or customized blockchain solution is required. **In this paper we addressed the following research questions:**  
**RQ 1: How many consensus protocols exist in 2022? **  
Various types of consensus algorithms have been devised over time for varying applications.