chain2 is an experimental cryptocurrency.  The main purpose of chain2 is to explore the performance of its difficulty adjustment algorithm: Real-Time Targeting (RTT). As a pure SHA256 PoW altcoin, chain2 competes for a share of the biggest pool of hashrate on Earth.

Miners and nodes wanted. This might be fun.


Download
https://github.com/chain2/chain2/releases


chain2 Mining - IMPORTANT

The RTT target starts low (difficulty high) and increases (decreases) during the block, depending the timestamp of the block being mined.  The next block's resulting nominal target is also included in the block template. It also rises with time, but is not the same as the actual target (see research paper).  Unmodified miners that rely on the template difficulty will fail to submit some valid blocks.

Slight (and hacky) modifications to pool software allow it to mine chain2 in a reasonable way, with no stratum client modifications needed:
 - ckpool https://bitbucket.org/dgenr8/ckpool/commits/26bfbcf5dd02f81094f92cbdda21802c3e132a64
 - yiimp https://github.com/dgenr8/yiimp-1/commits/next

The incentives established by this algorithm do not favor inaccurate timestamps, therefore using the timestamp as a nonce is not recommended.

chain2 lends itself to optimized mining pools and clients which understand RTT.  Please work on this if you can! An internal CPU miner is included for reference, but of course it is unusably slow.

Pools
https://mcpool.chain2.org/           -a sha256 -o stratum+tcp://stratum.mcpool.chain2.org:3330 -u -p c=CTWO

chain2 Specifications

- PoW algorithm: SHA256D
- Difficulty adjustment algorithm: RTT
   RTT research paper: https://github.com/chain2/chain2/blob/master/specifications/rtt.pdf
   RTT implementation: https://github.com/chain2/chain2/pull/6
- Starting difficulty: 1
- Starting target: 0x1d00ffff
- Block time: 10 minutes
- Block reward: 50 ctwo
- Block reward halving schedule: every 210,000 blocks
- Total coin supply: 21M
- Default P2P port: 9393
- Default RPC port: 9392
- Address format: cashaddr with "ctwo:" prefix (legacy bitcoin mode available)

- Pre-mine: No
- Founders reward: No
- Instamine: Not possible
- ICO: No
- Masternodes: No
- Segwit: No
- Finalization: No
- Genesis coinbase output script: OP_FALSE


BEWARE
If you somehow manage to buy ctwo from someone right now, you are extremely likely to lose money.  Chaotic reorganizations are quite possible. ctwo should never be worth anything unless it gains a meaningful level of stable miner support compared to BTC.


chain2 Consensus Rules:

    Bitcoin Cash rules as of 14 November, 2018 (PRE-SPLIT)
      (BIP143, 32MB blocks, etc ...)
    + Real Time Targeting
    + CHECKDATASIG activates at 75% support over 90 days (BIP135)
           * Activated 2020-07-29 12:14:35
    + Gradual max block size adjustment by miners (BIP100)


Reference implementation source code: https://github.com/chain2/chain2

Markets:
 - https://freiexchange.com/market/CTWO/BTC

Resources:
 - Explorer http://explorer.chain2.org
 - Explorer http://iquidus.chain2.org
 - Faucet http://faucet.chain2.org
 - Chat https://discord.gg/pydVnNh

Many BTC, BCH, and BSV applications are compatible with chain2 or could be made compatible with slight modifications.
Additional compatible implementations of chain2 are of course possible. PR's are also welcome to the chain2 reference implementation.


Consumer/Investor Disclosures

 - Cryptocurrency is a rapidly evolving technology.
 - Cryptocurrency has historically been EXTREMELY VOLATILE.
 - Transfers of ctwo are NON-REVERSIBLE.
 - Mined or transferred ctwo tokens may disappear in chain reorganizations.
 - The chain2 software is provided AS IS, WITHOUT GUARANTEE or WARRANTY.