Crown is the pioneer of Masternode Proof of Stake Consensus Systems (MNPoS)

MNPoS allows both masternodes and systemnodes to create new blocks and add them to the blockchain. Users do not need to run hot wallets to participate in the staking process

Crown Masternode Proof of Stake Consensus System Overview

The proof of stake consensus system for Crown allows both masternodes and systemnodes to create new blocks and add them to the blockchain. Users do not need to run hot wallets to participate in the staking process. Masternodes and systemnodes are required to have an amount of CRW “locked” (called node collateral) from use in order to be considered an active node and receive node rewards. In a traditional proof of stake consensus system a stake holder would consume their stake input (coins/UTXO) and be issued fresh coins that include the staking reward plus the value of the stake input that was consumed. Since being an active masternode or systemnode requires that node to keep their collateral untouched, this model is modified for Crown’s system.

Stake Pointers

Crown’s consensus system uses a new concept called stake pointers. A stake pointer can be thought of as a stakeable token that is given to masternodes and systemnodes, and is the input that is consumed by the proof of stake transaction. Stake pointers are “given” to masternodes and systemnodes when they receive masternode and systemnode rewards. Stake pointers are time sensitive (expire 2 days after being issued) and are what are used to determine whether a masternode or systemnode is at least "recently active". Since the list of active masternodes and systemnodes is not deterministic (not stored on the blockchain and is based on each peer’s interpretation of which have been validated) it means that simply checking if a node is considered active is something that could lead to unintentional forks because of disagreements from peers over which node may or may not be considered active. By using the stake pointer system, a peer is able to determine that the staking node was at least active within a recent period of time.

Stake pointers can only be used once. When a node stakes a block with their stake pointer, the pointer is marked as used, and the node will not be able to use that pointer again. If the node has multiple stake pointers, it will still be able to stake any of the unused pointers before they expire.

At the most technical level, a stake pointer is simply the transaction hash and the output position that a masternode or systemnode was paid their rewards in.

Stake Selection

Like traditional proof systems such as proof of work and most implementations of proof of stake, Crown uses a target difficulty for each block and the proof hash must be below the target value. A proof hash is done by hashing together the following inputs:

    Stakepointer Hash: The transaction hash that the node reward was paid.

    Stakepointer Output Index: The position in the vout vector that the reward was paid.

    Stake Modifier: The block hash that is 100 blocks before the stakepointer.

    Timestamp of Stakepointer: The time that the stakepointer was created.

    Timestamp of the New Stake: The time that the new stake was created.

By hashing the above inputs, a 256 bit proof hash is created. The value of the proof hash is then compared to the difficulty target value multiplied by the value of collateral that the node is holding (10,000 for masternode, 500 for systemnode). If the proof hash is less than the new target, then the stake is considered valid and can be used to package a block and add it to the blockchain. By multiplying the target value by the collateral amount, this means that the target is easier to hit for masternodes than it is for systemnodes.

Finding a Valid Proof Hash (Stake Mining)

Every input that is in the proof hash, except for the timestamp of the new stake, is constant for a given stake pointer. What this means is that if someone had two different computers with identical wallets and stakepointers, it would give no advantage to their ability to find a valid proof hash because they would produce the exact same hashes. Given the same set of inputs and using the same timestamp for the stake that is being created, the proof hash will always come out the same. What this means is that each stakepointer can simply create a new proof hash for every second that passes, and see if it is less than the difficulty target. If the proof hash is less than the target, the stake is packaged into a block and the node has successfully staked. If the proof hash is more than the target, the node waits another second and then tries creating a new proof hash. This process is continually repeated while a node has valid stake pointers.