What is Ethereum Classic, and should you care?

Earlier today, Ethereum successfully hard forked to recover hacked funds from the DAO. The Ether price has remained stable so far with no signs of a massive sell-off of the refunded Ether.

Note: I (scrawl) have written this article myself, it is not a repost or plagiarised article from CoinDesk, unlike most of the Ethereum news posted here...

A new project called "Ethereum Classic" is now emerging that seeks to retain the original "code is law" principle. Essentially, Ethereum Classic is keeping the non-forked blockchain going and so now there are two "parallel universes" of the blockchain. I am not going to argue on whether or not that is a good idea; my personal stance on the hard fork debate is a neutral one. But regardless of your thoughts about the hard fork debate, you may want to keep an eye on Ethereum Classic, because anyone who has owned Ether before the hard fork now also owns Ether Classic. This leads to the interesting prospect of selling your Ether Classic while keeping your real Ether untouched (or the other way around). Decentralised exchange BitSquare is already offering Ethereum Classic trading in their latest release.

Ethereum classic on Github

However, accessing your Ether Classic is not that simple. You see, the two "parallel universes" are not that parallel after all: a transaction in one blockchain can get picked up by the other blockchain, too. The only case where things diverge is when refunded Ether from the DAO is involved in the transaction. So how would you move your Ether Classic to an address without moving your real Ether to that same address? A solution is needed so you can actually spend your funds twice (once on each blockchain).

Developer Timon Rapp has written about this phenomenon calling it the "replay attack". In his article, he proposes a method to "split" one's funds so that they are controlled by an independent address on each version of the blockchain. The process essentially involves sending funds to a smart contract that can decide which version of the blockchain it is on (based on looking at the Dark DAO's balance). Once the funds are split, they can be moved independently without affecting their counterpart on the other blockchain.

Popular exchange Poloniex has announced they will split user funds appropriately, allowing anyone to withdraw their Ether Classic if wanted. No timeline has been announced yet for this feature.

In addition, for those interested in keeping their tokens from the losing blockchain as a keepsake, we will support a one-time withdrawal of the deprecated tokens, provided that the losing chain is still functional when you attempt a withdrawal. Specific instructions on how to access your tokens on the old chain to follow.

In the meantime, if you have some Ether in your own wallet and have not moved it since the hardfork, you can "split" your Ether using the process outlined by Timon Rapp.