Bitcoin Gold is a new open-source cryptocurrency, separate from bitcoin, but sharing with it the same past. Anyone who owns bitcoin (BTC) at the time of hard fork will receive the equivalent quantity of the new cryptocurrency, BTG.
The project was started by Jack Liao, CEO of Hong Kong-based mining hardware producer LightningASIC, and aims to “make Bitcoin decentralized again.”
Bitcoin Gold implements a different Proof of Work (PoW) algorithm than Bitcoin’s SHA-256. The new PoW, called Equihash, is ASIC-resistant, which means it is difficult for an ASIC (special computer hardware designed for cryptocurrency mining) to perform the block validation process faster than a high-end graphics cards (GPU).
In other words, Bitcoin Gold will be using the Equihash PoW to be mined by GPUs, not ASICs.
Except for the different PoW algorithm, Bitcoin Gold (or BGold) implements replay protection and different address formatting.
Bitcoin Gold adopts a much different difficulty adjustment algorithm called DigiShield V3, which will adjust difficulty in every new block.
Project's code is available at a GitHub repository.