Background

Mina Technical Paper is a product of years of meticulous research and tests that culminated into the world’s first provably secure proof-of-stake protocol for blockchains technically called Ouroboros Samasika . But before Mina, there were Bitcoin Network and Ethereum, both of which are currently the most successful blockchains pushing the boundaries of “decentralization” forward.

Legacy blockchains experience depleting full nodes

However one may consider the success of Bitcoin and Ethereum, they still have their drawbacks. Bitcoin blockchain size, as of the time of writing, was 344 Gigabyte, making it extremely expensive to run a full node. Even though Ethereum expects to transition to proof-of-stake by the end of 2021 fully, it is currently a PoW system. As plotted on Mina’s technical paper, full node operation on Bitcoin and Ethereum Network has continued to decrease over time because it’s becoming exorbitantly expensive to run full nodes.

Most users run a light node to address this, verifying only block headers but not transactions, or an ultralight node verifying nothing and relying on trusted advice from a trusted server, ironically undermining decentralization these networks were out to push.

The Mina solution

To solve this, O (1) Labs, the core team behind Mina, has designed a decentralized payment system that offers efficient verification of system history from genesis without relying on any external advice. Mina technical paper documents the dynamics of an extremely high throughput network, outlining a new method of verifying decentralized payment systems. As is the case with the scalability trilemma, one in Security, speed or decentralization has to go to achieve the other two. Its method does not necessarily sacrifice a key blockchain feature. Below is the simplified summary of the concepts documented in the technical paper. 

Although Mina is a payment-oriented blockchain offering similar functionality to Bitcoin, it is different in determining transactions. While Bitcoin adopts the UTXO model, Mina uses an account-based model just like Ethereum. An account-model blockchain system follows the pattern where the current state of the blockchain is a list of all account balances rather than a list of unspent coins (UTXOs).

A succinct blockchain network – Mina

In its extensive research, O (1) Labs posited that it is possible to compute a succinct non-interactive argument of knowledge (a SNARK) of any NP statement bringing about a state proof size of just 864 bytes which takes around 200ms to verify. Mina thereby presents the first provably-secure proof-of-stake (PoS) consensus protocol for succinct blockchains called Ouroboros Samasika. 

A succinct blockchain like Mina implies that any party with reasonable resources can be a full node, unlike in other legacy blockchains like Bitcoin and Ethereum, which require the role of light clients to cope with.

Incrementally computable SNARKS

Mina protocol is a succinct blockchain based on incrementally computable SNARKs. As already is, a blockchain is dynamic, and new blocks keep getting added to it. However, in Mina’s case, to ensure succinctness at any given point in time, it computes a new SNARK proof that validates the new blocks and the existing SNARK proof itself. A system in which a SNARK proof attests to the verifiability of another SNARK proof is what Mina refers to as an “incrementally-computable SNARK”.

Parallel scan state

Recall that a raw chain of blocks is inherently sequential (ie, cannot be parallelized generally). However, thanks to the incremental computability of SNARKs, the SNARK work can be parallelized, ie both block, and SNARK computation are not mutually exclusive. In essence, ‘parallel scan state’ necessitates the decoupling of block production from computing SNARK proofs. 


Mina Magazine is an independent publication not affiliated to Mina Foundation / O (1) Labs.
Mina Magazine is supported by Openbitlab.