Synopsis

VaporCoin is a simple blockchain transaction ledger implementation, built in Swift using Vapor.

Goals

Functional, simple and easy to understand implementation that favors learning over robust security and usability. This is not intended to be an 'altcoin'

Specifications

Blocks:

• Block time 60 seconds
• 6000 transactions per block (Effective 100 txns/s rate)
• Block difficulty updated every 60 blocks (hourly)
• Block reward 50 full units/block (1 unit = 100 000 000 sub-units)
• Block reward halved every 4 years (2 102 400 blocks at 525 600 blocks per year)
• Total amount of full units will be roughly ~209 829 375

Transactions:

• Simplified Bitcoin-style transactions, UTXO (No scripting capability)
• ECDSA signatures

Proof of Work (PoW) algorithm:

• Simplified Bitcoin-style. Single SHA256 hash of block header

Block header:

• Previous hash
• Merkle root of transactions in block
• UNIX timestamp
• Target difficulty
• Nonce (32 bit)

TODO

• JSON WebSocket p2p communication / Incomplete
• Peer discovery
• Locally hosted web interface to send and receive transactions, change settings and monitor blockchain status.
• Fractional difficulty adjustment (Using BigInt)
• Database logic
• Proper node syncing
• UTXO Transactions
• Establish consensus

Getting started

brew install vapor/tap/vapor

In project root directory:
vapor update
vapor build 
vapor run

If you are using Xcode, make sure to select `My Mac` as target, and select the `Run` scheme.

Difficulty Factor

To mine a block, you can lower the diffBits amount in Droplet+Setup.swift line 17:

let miner = Miner(coinbase: "coinbaseAddressNotImplementedYet", diffBits: 20, threadCount: 4)

Tips

Get me some coffee:

ETH: 0x1e8e9c1a1b71ff88829b962cfa7190d074343b37
LTC: LZc2QcyZGuhHF18s96VAUPpByZq2S8yCsj
ZEC: t1UukAm25iRLTyTQfhX6WfRBzMjp8UCmy4a