# PoW Tokens

## Proof-of-Work Backed Tokens#

In Ergo, one token per transaction can be issued, and the token id must be the same as the id of the box of the first input.

Thus if you have generated a box, you know the id of the future token. And this id is calculated via hashing.

Thus via iterating over a register (e.g. R4) used as a nonce, you can create a token with specific id properties, e.g. starting with a certain number of zeroes. So some work could be required in order to make such a token. Something like VanityGen-address in Bitcoin, but now VanityGen token )

Then some contracts may accept such PoW-backed NFTs only.

I haven't thought about use-cases, though. Maybe some are related to filtering out spam.

Full discussions here