Guide to Mina

Introduction to Mina

Mina aims to create a robust, decentralized network by making participation more accessible and less resource intensive. It is the first production grade succinct blockchain, designed to enable syncing and verifying the chain in seconds.

Mina will retain its proof-size, accessibility, and transaction speed even as the chain scales up to thousands of nodes. It achieves this by leveraging zk-SNARKs – certificates of correctly performed transactions that remove the need to verify the entire chain’s state. The use of zk-SNARKs is one of the core components of Mina’s innovative design.

“A zero-knowledge SNARK (or 'succinct NIZK of knowledge') is a SNARK satisfying a zero-knowledge property. Namely, zero knowledge ensures that the honest prover can generate valid proofs for true theorems without leaking any information about the theorem beyond the fact that the theorem is true (in particular, without leaking any information about the witness that he used to generate the proof for the theorem)." Source

zk-SNARKs consist of fixed size snapshots that represent a proof of the blockchain’s state transitions. Every time a new block is created, it takes a snapshot of itself, using the snapshot of the previous state as the background. That new snapshot will then be used as the backdrop for the next block, establishing a link between the changing states (blocks) without adding more computational load to the nodes that verify and secure state transitions.

This unique design enables participants to verify transactions without needing to store the full chain’s history, and minimizes the need for “trusted third parties” to provide access to the network.

In the future, developers will be able to deploy application logic on the Mina blockchain in the form of Snapps, SNARK-powered Applications. These applications will function similarly to applications on other blockchains, but will enable enhanced privacy features due to the chain’s native ability to verify data without disclosing the data itself.

How to participate on Mina

At a high level, the Mina protocol is made up of the consensus mechanism (Ouroboros Samasika), blocks, fixed size snapshots that provide the blockchain’s state summary (zkSNARKs), the state transition mechanism for SNARKs, and a marketplace for block producers and SNARK producers to interact with one another.

Although every new block must include a zkSNARK, block production is decoupled from computing SNARK proofs; this structure is referred to as parallel scan state. In this way, transaction speed won’t slow as new transactions are added to the network, allowing the network to scale well as demand for transaction bandwidth increases.

These two streams of work — block and SNARK production — come together in the SNARKetplace. This marketplace is where block producers purchase SNARKed state transitions from SNARK workers, in exchange for some part of the total transaction fees earned by the block producer.

The Mina network is made up of the following key functions/nodes:

• Validator nodes ("block producers"): Validator nodes are responsible for validating transactions and committing new blocks to the blockchain. As with other proof of stake networks, nodes are selected to perform work on the chain based on the amount of mina staked and delegated to the node–the node’s “stake weight.” The higher the stake weight, the higher the likelihood of said node being selected as a block producer. In exchange for its work, the node earns rewards and transaction fees.

• SNARK workers ("Snarkers"): SNARK workers are network participants that produce zk-SNARKs to verify transactions. Block producers post “asks'' on the SNARKetplace setting the minimum acceptable price for SNARKs and SNARKers compete to meet those asks with “bids.” Block producers purchase the most competitively priced zk-SNARKS and pay the SNARKers out of the coinbase reward and transaction fees they earn for their work on the chain.

• Archive nodes: Archive nodes keep the blockchain data in an uncompressed (unSNARKed) database, in order to provide easy access to the chain’s history.

By definition, every node, regardless of whether it takes part in block production or not, is a full node in Mina. A full node is a node in a blockchain network that can independently verify all transactions and the current state of the network. Mina expects all network participants to be capable of performing this verification work. Because Mina uses recursive zk-SNARKs to continuously prove state validity, full-node security is achieved by simply downloading a zk-SNARK, which is only a few hundred bytes and takes a few milliseconds to verify.

Block production on Mina

Mina also enables delegation. Delegators can stake their own mina to any block producer in exchange for a predetermined portion of the rewards (dependent on the what the terms the validator offers), minus any validator fees. Block producers are randomly selected for work on the chain, proportional to the amount of staked mina on the node (stake includes both self-bonded and delegated tokens). The more total mina staked to a node, the higher the probability it will be selected to produce a block.

On Mina, time is divided into slots and epochs; a slot is 3 minutes and an epoch is a collection of 7140 slots. Multiple blocks can, and usually are, produced within a slot. Initially, Mina’s active set is expected to consist of hundreds of block producers. The active set is determined at the beginning of each epoch, based on the distribution of nodes from 2 epochs prior. From that active set, a slot leader is randomly selected to produce and broadcast the next block. Rewards are calculated at the end of the epoch.

When a block producer is selected for a slot and successfully produces a block, the winning account (i.e. the node operator or one of the delegators to the block producer node that secured the chance to produce the block) is tagged, signifying attribution of the reward–depending on their share of the stake weight. For example, if a delegator represents 90% of the stake weight on a validator node, there is a 90% chance that every block reward won by the validator will be tagged with that delegator's ID.

Rewards and economics on Mina

The effective reward rate on Mina is based on the staking rate of the total supply of mina in circulation. If every token is staked, then the reward rate is equivalent to the inflation rate and will follow its schedule. Inflation is benchmarked at 12% for the first 2 years and will adjust 1% downwards every six months thereafter; over time it will stabilize at 7% annually.

"Mina protocol supply schedule" from the Mina Whitepaper

It is targeted such that as the percentage of total tokens staked decreases, the reward rate per staker increases. For example, if only 50% of tokens are staked rather than 100%, the reward rate doubles from 12% to 24% in the first year and 7% to 14% in the long run. This feature will not be available at mainnet launch but will be added in the months after.

"Block reward multiplier by participation rate" from the Mina Whitepaper

Some participants in the network will have time-locked tokens, meaning their tokens are subject to a predetermined vesting schedule. In order to incentivize participants with non-time locked tokens to stake their mina, Mina offers those accounts double the rewards. These “supercharged” rewards apply to all accounts that qualify, both block producers and delegators. If an account holding non-time-locked tokens delegates to a block producer holding time-locked tokens, and the block slot attribution carries the tag of that delegator, the rewards are doubled.

Currently, a large part of the rewards distribution to delegators in Mina is performed off-chain; node operators are responsible for both calculating the resultant payouts to delegators and initiating/executing the equivalent transactions. Ultimately, it is up to their discretion if rewards will be distributed to all parties equally or based on who is tagged as winning the slot, particularly as related to supercharged rewards.

Because Coinbase Cloud's services are non-custodial and can never handle a customer's tokens, we can only support customers interested in operating nodes that are willing to be responsible for reward distribution to their delegators, or are not planning to have delegations. Mina intends to add on-chain distribution in the near future and at that time we will be able to offer support for block producers with delegators.

Risks of participation on Mina

There is no slashing in Mina. Instead, the protocol designers hold that the opportunity cost of downtime, reputational damage, and missed delegations will be enough to discourage downtime and malicious behavior.

If a node shares bad data with the network, their trust score decreases, which can result in a temporary ban – enforced by network peers – preventing the block producer from earning rewards and discouraging delegators from working with them. The combination of these assumptions have been tested in agent-based simulations, and a report showing slashing isn’t necessary to enforce security is available here.

Why run a Mina node?

• Running a node helps the network function properly and remain secure. It is a critical step to maintaining the shared network state.

• The inflation rate — and therefore reward rate — is higher for the first two years after Mina launches, and is dependent on the staking rate. Running a node on day one allows you to optimize your participation in the network.

• Mina allows token holders to delegate so a node operator can earn additional rewards from delegation fees.

• If you or your delegators have non-time locked tokens, your node can earn supercharged rewards (2x) for producing a block.

• Rewards accrue and compound automatically.

"As a professional validator and leading infrastructure provider for enterprises seeking exposure to cryptocurrencies, our partnership with Bison Trails [now Coinbase Cloud] expands opportunities for involvement in Mina to the world's top custodians, exchanges, and funds."— Evan Shapiro, CEO and Co-Founder of O(1) Labs, the team incubating Mina

Why choose Coinbase Cloud?

Coinbase Cloud is uniquely positioned to provide unparalleled enterprise-grade node infrastructure for Mina block producers:

• Enterprise-grade infrastructure security: As one of the most trusted names in the blockchain infrastructure industry, we have best-in-class security augmented by information, application, and incident management policies.

• Easy-to-use platform: We designed an intuitive user experience that is surprisingly simple given the complexity of the underlying technology. Our platform’s automatic node management workflow frees our customers from the worry of constantly checking or managing their active participation. We also keep our customers in full control.

• Protocol experts: We are node, participatory infrastructure, and protocol experts. We test all software, infrastructure, and protocol upgrades on our own infrastructure first ensuring any breaking issues are caught well before propagating changes to our customers’ infrastructure.

• Access to protocol specialists: Our dedicated protocol specialists keep Coinbase Cloud's customers up-to-date about changes to the validator ecosystem. They provide advice, insights, and guidance that arms our customers with critical information to better manage their participation.

• Premium provider: We are the world’s premier multi-cloud, multi-region infrastructure provider specializing in permissionless participatory networks.

• Custodian agnostic: As a non-custodial infrastructure provider, we can work with you to participate in Mina regardless of your custody solution.