Permissioned network

As explained in Real-World Cryptography

A network in which participation in consensus is restricted to a fixed or authorized set of participants.

A permissioned network restricts consensus participation to a known, fixed set of authorized participants. Unlike a permissionless network, it does not allow anyone to join consensus. section 12.1.3 section 12.5

Its practical shape is easiest to see through the roles it assigns:

• Known participants, rather than anonymous open participation, form the consensus group. section 12.1.3
• BFT consensus protocols can operate with this fixed participant set; proof of authority may determine membership, while proof of stake may elect it dynamically. section 12.5
• Restricting participation makes a different consensus design possible from Bitcoin’s proof-of-work permissionless model. section 12.1.3 section 12.5

DiemBFT validators

Diem operates in a permissioned setting where validators are known in advance. A designated validator proposes a block, others vote, and a later leader gathers enough signatures into a quorum certificate before extending the chain. If a leader is inactive, validators time out and advance to the next round. section 12.4.2

Figure 12.1 A centralized network can be seen as a single point of failure, whereas a distributed and decentralized network are resilient to a number of servers shutting down or acting maliciously. A permissioned network has a known and fixed set of main actors, while in a permissionless network, anyone can participate.

Compare centralized, distributed, decentralized, permissioned, and permissionless network structures in one visual overview. section 12.1.3

How Real-World Cryptography covers it

How deep it goes

Defines membership and contrasts open participation, then works through a DiemBFT round without detailing membership governance.

Examples

Uses DiemBFT validators, rotating leaders, signed votes, quorum certificates, and timeout-driven rounds.

What you can do after

Evaluate whether a consensus design assumes authorized participants or open participation.

How it connects

Connects permissionless networks, Byzantine fault-tolerant consensus, proof of authority, proof of stake, proof of work, and quorum certificates.

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Related concepts

• permissionless networkcontrasts with · A permissionless network is a network that allows anyone to join and participate without authorization from a central administrator.
• proof of authorityconfigured by · Proof of authority is a consensus-participant selection mechanism that relies on authorized identities or authorities.

This explainer was generated by Manning's knowledge graph from the text of Real-World Cryptography. The section links point to the parts of the book it draws on.