Résumé

Permissionless blockchains are open for anyone to use. You can even participate in their consensus mechanisms, provided you meet specific conditions. Bitcoin, Ethereum, and BNB Chain are all examples of permissionless blockchains, which are generally transparent and decentralized.

Permissioned blockchains, on the other hand, require invitations to join. They are generally used in private professional contexts and adapted to certain use cases. Power is limited to a small group of validators who make most of the decisions regarding the network. Transparency may be limited, but network upgrade time and scalability are often greatly improved.

Introduction

Have you ever thought about what type of blockchain you are using beyond whether it is proof of work (PoW) or proof of stake (PoS)? Every blockchain can actually be considered permissionless or permissioned. Understanding these two categories can help you learn more about the characteristics of a blockchain and how fluid it is.

What are permissioned and permissionless blockchains?

There is more than one type of blockchain. One of the most important distinctions is whether a blockchain is permissionless or permissioned. You are most likely already familiar with permissionless blockchains, which anyone can use. Use of the network and participation in the validation process are also open to everyone. Bitcoin, BNB Chain, and Ethereum are all permissionless blockchains.

A permissioned blockchain requires that participants receive permission to participate. These blockchains are generally used in a private setting, for example within an organization or a company. For example, a company can use the Hyperledger Fabric blockchain framework to create a permissioned blockchain for its supply chain system. If you want to participate in the network, an administrator must specifically grant you access.

Brief history and context

Blockchain technology dates back to Satoshi Nakamoto’s bitcoin white paper. The technology presented in the white paper is a permissionless blockchain through which users generate consensus without consultation. This permissionless trend has continued, with the Bitcoin model influencing several generations of blockchains. The values ​​and ethics of Bitcoin and its descendants are adapted to public and permissionless blockchains.

The characteristics of blockchain have also proven to be attractive for private applications. Its immutability, transparency (in certain respects) and security have created a need for blockchains to offer an alternative experience that includes operation dependent on access authorizations.

To meet this need, blockchain developers have created permissioned frameworks or custom blockchains for use by third parties. As mentioned earlier, Hyperledger Fabric is one such framework. Quorum, MultiChain and Ethereum Geth also provide private structures for business needs.

main Features

The characteristics below do not always apply to all blockchains whether permissioned or permissionless. However, in general, you will find that most of them meet the standards presented.

Advantages and disadvantages

Permissionless Blockchains: Advantages

1. The potential for decentralization. Not all permissionless blockchains are decentralized, but they generally have the potential to be highly decentralized. Anyone can participate in the consensus mechanism or use a network without permission if they want to and have the resources to do so.

2. A group consensus. Users can actively participate and decide on network changes. Validators and network users can also “random vote,” and unpopular changes can lead to the creation of forked versions of a network.

3. Ease of access. Anyone can create a wallet and join a network without permission, as these networks are easily accessible and have relatively low barriers to entry.

Permissionless blockchains: Disadvantages

1. Scalability Challenges. Permissionless blockchains must handle large user bases and high traffic volume. Network upgrades to improve scalability must have group consensus to be implemented effectively.

2. The presence of malicious actors. Since anyone can join blockchains without permission, there is always a risk of encountering malicious actors on these networks.

3. Excessive transparency. Most information on permissionless blockchains is free for anyone to view, posing potential privacy and security concerns.

Permissioned Blockchains: Advantages

1. Scalability. A permissioned blockchain is typically managed by an entity with some degree of control over the validators. So upgrades can be done quite easily.

2. Easy customization. A permissioned blockchain can be built for a specific purpose, making it effective for a particular function. If needs change, blockchain can be easily customized.

3. A controlled degree of transparency. An authorized blockchain operator can determine an appropriate level of transparency for the network, based on its use case.

4. Entry by invitation only. You can control exactly who can and cannot participate in the blockchain.

Permission-enabled blockchains: Disadvantages

1. Centralization. Power is likely controlled by a central entity or a small group of validators chosen by the blockchain owner. This means that network decisions are unlikely to include all stakeholders.

2. Vulnerability to attacks. Permissioned blockchains generally have fewer validators, making their consensus mechanism less resistant to attacks.

3. The risk of censorship. Collusion on the network network or updates introduced by the blockchain operator present a risk of censorship. If enough actors agree to do so, the information on the blockchain could be modified.

Should I use permissioned or permissionless blockchain?

The answer to this question is quite simple. If you are looking to create a service that is open to everyone, you need a permissionless blockchain. However, having a permissionless blockchain does not mean you have to follow the standard set of principles and goals. In fact, your blockchain could be centralized and permissionless at the same time. You can also include other privacy elements if you wish.

If you are looking to use a blockchain in a private environment, such as a business or government, a permissioned blockchain would be more suitable. Again, your blockchain does not have to follow the usual characteristics associated with permissioned blockchains; it could be completely transparent and open to public view.

Conclusion

Although you will likely only encounter permissionless blockchains as a cryptocurrency investor or trader, it is helpful to understand how they are different from permissioned blockchains. It’s easy to have a singular view of distributed ledger technology (DLT) that fits the transparent, public, and decentralized crypto model. However, these settings may change. In fact, many private companies use permissioned blockchains that do not fit the conventional idea of ​​blockchain.

More information

• What is blockchain technology? The ultimate guide

• Permissionless Blockchain

• How does a blockchain work?