Scroda’s Sub-Zero Protocol Walkthrough

Scroda
4 min readJul 5, 2019

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The Sub-Zero Protocol permits Scroda to achieve Sub-Second Zero-Confirmation Transactions all due to two chains coming together and becoming one, Yin and Yang.

Blockchains to this day verify transactions on a block to block basis thus allowing for attacks such as the reversal of transactions through a 51% attack. This walk-through will help you understand how the harmonization of both chains working together to process transactions, enables Scroda to obtain security while allowing for it to scale.

The use of relay chains, the establishment of an order-of-events, and the verification of transactions on a transaction to transaction basis before permanently being placed on the Scroda main chain through the use of pBFT consensus alongside the use of Scroda ID allows for zero-confirmation transactions in sub-second time.

Yin is the chain in which is centralized; the bad in blockchain, while still showing properties in which are good for its users; its ability to scale. The yin chain solely focuses on establishing an order of events, through the use of a rotating leader, moving away from approaches seen in competitors in which utilize a committee.

All committee members’ votes are counted with equal weight and recall that in Thunder’s consensus paradigm, ¾ fraction of votes must be collected to confirm a block on the fast path.

[https://medium.com/thundercore/committee-election-in-thundercore-pos-scheme-2d7163555997]

  • Throughput: The use of a rotating leader allows for Scroda to achieve an estimated 500k+ TPS in which are seen in other projects in which utilize a rotating leader.
  • Latency: Leaders are able to establish an order of event in sub-second time.

Yang is the chain which is decentralized thus providing security, the good in blockchain; sluggish, a property in which is bad for its users. The yang chain focuses on verifying transactions after an order of event has been established on the yin chain, having a trail to now follow. This trail allows for all nodes on the Scroda platform to verify transactions together and reach consensus on a transaction to transaction basis before being placed on the mainchain; offering a fork free environment.

The harmonization of both chains working together in the processing of transactions allows for zero-confirmation transactions to come to life. When a sender transmits a transaction and after a order of events has been established on such transaction on the yang chain, the receiver is able instantly verify on their own if such transaction is true and if true be assured that it will be processed from the security that is provided from the yang chain.

Technical Overview [Included 08/26/2019]

The yang chain maintains a list of active nodes which is updated along with every new verified block on-chain. The yin chain pulls this list from the yang chain and establishes a set of enforcers and leaders from it.

Upon the elected leader presenting his list of ordering of events along side the current valid hash header the valid header is then updated and the leader is rotated. The next leader submits his list alongside the current valid hash header, if a leader fails to submit a list withing the current time allocated the established enforcers will vote upon the leader being faulty and a new valid hash header will be generated alongside with a new leader.

  • A new set of 20 enforcers is established every time a new active nodes list is established.
  • Enforcers rotate only when one is found to be faulty by having failed to vote or by being malicious.
  • Leaders and Enforcers may be pulled from the same active nodes list until updated being that the yin chain works faster then the yang.

Assuming that blocks are verified at a rate of 5 minutes per block on the yang chain we can assume that leaders would rotate 300 times per each active nodes list generated if rotating per second. Each node on the active nodes list must commit to being online for those 5 minutes or risk being penalized.

What are your thoughts?

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Scroda

A Democratic Blockchain focused on privacy that ensures to give power and a voice to the people.