In most jurisdictions, copyright is automatic. If you put no license on the code, the default is "all rights reserved"; that is, no one can do anything with it.

Yes, that's my intention, almost: no one can legally do anything with it. Private persons usually ignore these laws generally and get away with it.

The fair use Microsoft thinks it has would still apply. Good luck going up against the lawyers who signed off on this.

Huh? What if someone else claims they wrote your code and slaps a license on it?

When its my IP i can enforce it, send them a DMCA or sue them for damages. They used my stuff without having a license to do so. If they slapped an own license on it, granting others permission to it, that would increase the damages.

Ok, but you'd have to prove it.

For git repos, include the current revision of your master branch as metadata to an SEPA transaction. This is a legal solid proof that you had code at time X.

Interesting. Has anyone automated this?

It reminds me of:

https://notary.bitcoin.com/

However, it does not prove that your version of the repository was the first and original one.

I consider the SEPA tagging a secondary method. If someone was to contest the authorship of my code, i'd challenge them to explain why certain passages were written in that way. Or how specific magic numbers were picked. Linus for example used the birth date of his daughters as magic numbers for the reboot() syscall.

Generally i do recommend to avoid cryptocurrencies for anything serious. Its public image is beyond repair.

They could do that if you licensed it too. It would be illegal just the same.

Copyright is independent of license.