On the forum there were some threads about people creating multiple public keys from one private key. I am wondering if the reverse is possible as well. Can 2 private keys create 1 public key. I am talking about two private keys of 64 characters.
Is this possible and if so how?
There are three different terms:
The address is derived from the public key. The public key is derived from the private key.
Since address is shorter than a private key, multiple private keys map into the same address. Therefore an Ethereum address can have multiple valid private keys.
Of course it's next to impossible to find a private key for an address (or for a public key) even if you already have one valid private key.
In short, no. The process of creating a key pair is pretty much one-directional, and the reverse is hardly possible. By the way, why would you like to pull off a reverse?
Here's a good example of how this all works under the hood. It's YAD's interactive guide for beginners where you create the key pair step by step. But if you don't want to click, here's a short version:
Generate a private key using some degree of randomization. Along the lines of bitaddress.org or similar services.
Generate a public key from your private key using ECC (specifically the secp256k1 curve, which is a good fit for Ethereum).
Generate a public address out of the public key, which might also consist of generating a compressed public address, then refining this address, etc
See now how the right order of these steps is actually important, right? Hopefully, now you don't want to mess with it.
