Application layer
Model layer
Business Logic
Mitum Blockchain Network layer
Blockchain Core

Protocon Network is a blockchain network based on the Mitum Mainnet.ISAAC+, Mitum's consensus protocol, was developedbased on the PBFT consensus algorithm.

Mitum is designed for large-scale data processing for use in real industries,
and has universal availability for use in all areas requiring blockchain technology.

Technical Features

Can be utilized in a wide range of business areas
Implement maximum levels of decentralization
Ideal for large data processing(Maximum processing speed of 5,000 tps)
Network designer exists
Able to use private keys of other platforms
Account management functions are separate form private keys
Can be combined with various databases
AVL Tree speeds up internal data retrieval
Promise liveness & safety as well as finality

Protocon Ecosystem

ISAAC+ divides Consensus Nodes into Suffrage and Acting Suffrage Group,and selects new leader for each new block-building process(Round).

Non-Consensus Node Group:
  • A group that is comprised of ordinary people with node operating level of technical knowledge. 
  • Responsible for backing up agreed blocks and providing data when there is an external data lookup request.
Suffrage Group:
  • Node groups with a certain level of processing power and reliable network bandwidth.
  • Participate in consensus at a certain point and contribute to block creation.
Acting Suffrage Group:
  • The group that is selected from Suffrage Group randomly each time the Round changes.
  • One of the members of the group becomes a Proposer and sends a message to the rest of the nodes.

ISAAC+ Consensus Protocol

ISAAC+ is consensus protocol of Mitum.ISAAC+ is a consensus protocol modified from PBFT(Practical Byzantine Fault Tolerance) and guarantees finality of blocks along with Liveness and Safety within the restricted Fault Tolerance.


  • Compensate liveness of PBFT model and maintain decentralized network by automatically withdrawing and entering nodes from Consensus Nodes that meet certain conditions.
  • Increase processing capability by letting Suffrage Group focus only on consensus and model data processing.
  • Introduce Non-Consensus Node Group and energize community.

Phases of Consensus Protocol

ISAAC+ is an improved version of the previous consensus protocol, ISAAC.

The consensus phase of previous consensus protocol, ISAAC is 4 phases: Init - Sign - Accept - All Confirmand is similar to the 4 phases of PBFT. ISAAC was named after the first letter of each phase I-S-A-AC.Currently, ISAAC+ consists of 3 phases: Init - Sign - Accept.

Init Phase

  • All nodes(Suffrage Group) that participate in consensus verify the agreement on the block created from the previous Round and send the result to Suffrage Group in a ballot.
  • If an agreement is not reached, the next Round of Init phase will be started again and the voting will be proceeded once more.
  • If the agreement is successfuly made, the block generated from the previous round will be recorded on the blockchain and a new round will begin. The Suffrage Group records the agreed block on blockchain before entering the Sign phase.

Sign Phase

  • Using Random function, select the Proposer and Acting Suffrage Group member that will propose block creating for this round.
  • Acting Suffrage Group verify Proposer's Proposal and sends the result to the entire Suffrage Group. Even if the agreement in Sign phase among Acting Suffrage Group is not successful, enter the Init phase if the agreement is successful at the Accept phase based on what the Acting Suffrage Group sent to the Suffrage Group.

Accept Phase

  • Enter into the next round of Init phase if the agreement in Accept phase is successful based on the information sent from Acting Suffrage Group to Suffrage Group.

Decentralization Strategy

In PBFT, nodes are not freely accessible and as a result, token economy and governance structurethat controls monopoly should be considered at the same time to maintain decentralized status.In this respect, the Protocon Network will carry out four-step strategy for a decentralized network.
Jeju Net
Centralized Network
Beijing Net
Consortium Network
New York Net
Semi Decentralized Network
Seoul Net
Fully Decentralized Network

Jeju Net

  • Private Boots from a private network and the foundation makes decisions.
  • Build experience on network stabilization and node opereation.
  • Derive best fee strucure by calculating network operating costs and incidental costs.
  • Provide service by linking BlockSign and Blockcity.

Beijing Net

  • Initial model of decentralized governance structure.
  • Aim to expand into a sort of consortium network.
  • Start operating the node compensation structure.
  • Non-Consensus Node participates in network operations.
  • Introduce two decision making agents, Node Committee and Congress.

New York Net

  • Early stage of decentralized network.
  • Operate most nodes by external participants.
  • Stabilize of the node compensation structure.
  • Introduce automated approaches to participation and retirement of nodes.

Seoul Net

  • Create DAOs that have fully decentralized node operations and governance structures.
  • A decentralized, global community runs the network.
  • Adopt sophisticated and structured governance rules.