can't you just view the progression of the block creation on
https://mempool.space/ , calc the perfect timing to tranfer and just do it in about a minute?
No. Because noone knows when the next block will be created. It's possible the next block get mined in 55min, or 90min or even 2 hours. There's no guarantee it'll be mined within the next 10 minutes, it's just an average value.
Prove that you have the 66 private key by sharing the SHA-256 of the public key. This way we can verify if the address is correct
No one will be able to derive the public key, but we can verify that you have it
why the sha256 hash of the
public key and not simply publish the sha256 hash of the “
PRIVATE” key instead? Sha256 is secure and there is no way backwards to get the private key. This would mean that everyone in here could only check
afterwards whether the person knew the correct private key, i.e. only after the pubkey had been made public by a TX.
There's no difference between SHA256(PubKey) and SHA256(PrivKey).
By the way adding salt would be better since bruteforcing SHA256(PrivKey) is much easier than bitcoin directly.
So, SHA256(PubKey) or SHA256(PrivKey+salt) are both safe.