## 6 Key Findings
### Open Challenges and Future Work
#### 6.2.4 Decentralized Reputation and Incentives  
It must be remarked that decentralized networks must be driven by some kind of reward to ensure long-term activity. When consortiums are competitive and led by profit, a common incentive is the data shared by the different stakeholders. However, the incentives of academic environments are different. In fact, the aforementioned issues regarding the current verification procedures and the lack of trust are an important incentive for academic institutions and organizations to maintain trust around their data.  
The literature has extensively studied the impact of incentives within decentralized networks. For example, in [117] the authors classified incentives into three subcategories: reputation, tokens and staking revenues. Precisely, the reputation-based weighted voting incentives the individual to gain additional (non-tradeable) reputation, which leads to more influence in voting. Surprisingly enough, after reviewing 220 public DAOs, they found out that the existence of incentives do not positively influence DAO long term viability. However, this is not an empirical conclusion, and more research is required to fully understand the impact of reputation mechanisms.  
The ERC20 (Fungible Token Standard) can enable a reputation mechanism, where universities or certifying bodies (i.e., a certificate scenario could go beyond academia) could earn tokens for maintaining the trust in the network (e.g., adapting to the consensus algorithm, transparent issue of records). However, the tradeable nature of ERC20 tokens makes it unsuitable for many cases, as reputation should not be traded.  
Reputation and penalty algorithms can be set based on the performance of participants. For instance, a reputation algorithm could assess an organization reputation considering its CO2 emissions or the provider's punctuality of commodity delivery in a supply chain management scenario. In the case of the platform presented in this article, reputation could be based on the total number of credentials issued by the system, on the number of verification requests or on the institution revocation rate.  
Finally, it is also worth mentioning that the ERC721 standard unlocks many possibilities within several domains, specially in the academic field [118]. NFTs can be modified so that, once transferred, they cannot be exchanged again. Thus, NFTs can represent badges, trophies or achievements related to academic merits and that would be publicly visible. Students would be encouraged to earn them, as they would be representative of the student's performance or skills [119]. This is related with the concept of gamification, which can be applied to other domains [120]. The tradeable nature of the tokens may make them unsuitable for certain use cases. In recent years, some authors have explored the use of soulbound tokens, a type of NFT that remains in the possession of an individual or entity permanently [121; 122]. Therefore, the concept of soulbound tokens could better fit an academic platform like the one proposed. For example, trust certifications can be assigned to certain actors in the form of soulbound tokens, which are non-transferable.