09/23 - Hybrid Consensus Hard Fork

[pai4eva]

Project PAI: Hybrid Consensus Hard Fork

THE INFORMATION IN THIS DOCUMENT IS CRITICAL TO ALL USERS OF PAI COIN. PLEASE READ.

Summary

The Project PAI Blockchain will fork to a new PoW/PoS Hybrid Consensus mechanism using an alternative, SHA-3/SHAKE-256 hashing algorithm. This hard fork is mandatory, non-backwards compatible, and there are no provisions for a separate “Original PAI” to continue.

Updating to the new version is as simple as rebuilding paicoind using the 2.0.001 tag from the official repository. See here: https://github.com/projectpai/paicoin/tags. Once your node is updated, no further intervention should be required. All existing RPC/CLI commands and usage will remain the same, though some new commands will have been added.

Goals

Following recommendations set out by the research paper, Prospective Hybrid Consensus for Project PAI, Project PAI Core Developers have been working on a “Hybrid” Proof of Work/Proof of Stake consensus mechanism for the next iteration of the PAI Blockchain. The primary goals of this fork are to:

1. Remove the current whitelist that prevents the public from mining freely. The whitelist was originally implemented to disincentivize 51% attacks and other malicious activity. These vulnerabilities will be alleviated by the PoS portion of the Hybrid implementation.
2. Move away from hashing functions known to be supported by ASIC devices, thereby reducing the barrier to entry for mining. This will theoretically enable greater participation in mining.

Execution

Execution of the hard fork will consist of a series of dependent events, starting with the hard fork itself, when all updated full nodes switch to using SHA-3 mining; followed by an Interim Transition Period (ITP), during which software components required for staking are incrementally enabled. The ITP concludes with the removal of the mining whitelist, at which point public Hybrid PoW/PoS will be fully enabled for PAI Coin,

Hard Fork

The execution of the Hybrid Consensus hard fork process is scheduled to begin at block height 154,550 on mainnet. Barring significant changes in hash rate, this corresponds to approximately 10:30 AM PDT (5:30 PM UTC) on October 6, 2020.

Interim Transition Period

After the forking block height, the blockchain will enter an Interim Transition Period (ITP) during which software components required for staking will be incrementally activated. The ITP will proceed as follows:

• Mainnet Fork at Block 154,550
  • Approximately 5:30 PM UTC on October 6.
  • At block height 154,550, all full nodes running PAI Coin Core v2.0.001 will switch to Hybrid Consensus. The immediate impact at this point is that mining will switch to using SHA-3/SHAKE-256. Staking will not yet be enabled, the mining whitelist will still be enforced.
• Purchasing of Stake Vouchers Enabled at Block 154,806
  • Approximately 12:10 PM UTC on October 8.
  • At block height 154,806, 256 blocks after the initial hard fork, all full nodes running PAI Coin Core v2.0.001 will begin to accept blocks that include Stake Voucher purchase transactions. The Stake Vouchers (SVs) themselves will not yet be eligible to vote on new blocks.
• Stake Vouchers Begin Voting at Block 155,574
  • Approximately 2:50 PM UTC on October 15.
  • At block height 155,574, 768 blocks after purchasing of SVs is enabled, all full nodes running PAI Coin Core v2.0.001 will begin to require that vote transactions be included in new blocks.
• Mining Becomes Public (Whitelist Removed) at Block 155,718
  • Approximately 2:50 PM UTC on October 16.
  • At block height 155,718, 144 blocks after requiring votes on new blocks, the mining whitelist will stop being enforced, and valid blocks specifying any coinbase payout address will be accepted. This will complete the transition to Hybrid PoW/PoS Consensus.

Preparation

What you need to do in preparation for this Hard Fork depends on how you use PAI Coin.

Full Node

If you run a full node (which you would be doing if you are running paicoind from the official Project PAI GitHub repository), you will need to update your PAI Coin software prior to the fork. If you do not, your node will stop functioning properly after the fork. Fortunately, updating should be straightforward.

You simply need to:

1. Update the local version of your paicoin codebase to tag 2.0.001
2. Build paicoind per the instructions in doc/build_unix.md

Once complete, you should be able to verify you are on the correct version by executing:

paicoind --version

And you should see:

PAIcoin Core Daemon version v2.0.001-[build]

Note that the dependencies and build requirements for paicoind have not changed with this release. Likewise, all currently available RPC/CLI operations for paicoind are still present and fully backward compatible. Some new commands have been added.

You can find detailed information on how to set up, run, and maintain a PAI Coin Full Node here:

Building and Maintaining a PAI Coin Full Node

[Project PAIA logo] Hosting a PAI Coin full node is one of the best things you can do to support Project PAI. It’s simple and affordable to do, and it helps to ensure good network performance and reliability for PAI Coin. This document outlines how to properly build and maintain a PAI Coin full node. Table of Contents 1. What is a full node? 2. Obtain a computer or server to act as a node Cloud computing Self-hosting 3. Install PAI Coin Core Installing dependencies and configuring your…

PAI Up Mobile

You will need to update your PAI Up Mobile app prior to the fork in order to continue using it. The newest version for Android will be available for download from https://paiup.com. A safe and straightforward distribution mechanism for iOS is being researched and will be announced soon. We strongly encourage you to write down your paper key (12-word seed phrase) before updating PAI Up. This will ensure you do not lose access to your wallet and coins if something goes wrong during the update.

PAI Up Web

No changes are necessary. However, the PAI Up Web Wallet will be inaccessible for several hours before and after the fork execution until stability of the post-fork blockchain is confirmed. The exact timeframe of the suspension of PAI Up Web functionality will be announced closer to the hard fork time.

PAI Coin Pool

No changes are necessary. However, PAI Coin Pool deposits and withdrawals will be disabled for several hours before and after the fork execution until stability of the post-fork blockchain is confirmed. The exact timeframe of the suspension of deposits and withdrawals will be announced closer to the hard fork time.

Huobi and other exchanges

If you are a user of Huobi, or other platforms that exchange PAI Coin, please contact them directly for information. It is conventional that they will disable deposits and withdrawals for a period before and after the fork execution.

Conclusion

We are very excited to finally make the work we have been doing on this version of PAI, public. We believe that it will position PAI for a long and fruitful future. Thank you for your continued support in making Project PAI a success!