Before the merge, you should understand what a replay attack is and how to protect yourself from it!

With the upcoming Ethereum Merge, I think we're all due a reminder of what replay attacks are, and what we can do to avoid suffering from them.

To that end, here is an interesting Twitter thread from @OlimpioCrypto that explains it clearly:

https://twitter.com/OlimpioCrypto/status/1557751718905090048

Now, the ETH PoW devs are planning on changing the chainid to prevent replay-attacks from happening, but they haven't done it yet and the Merge is coming too soon to ignore the risks.

At this stage, even Coinbase is worried about the state of the PoW fork: https://github.com/ethereumpow/go-ethereum/pull/17

Be safe. :)