Hi there

As I don't speak italian, I read your post through google translate, I hope I understood it well.

When you stamp your file through stampd.io, the files unique ID hash is posted on the Blockchain. The file itself plus the blockchain post (which can be traced through the technical details in stampd's certificate) can prove to anyone that the specific file existed at the time of the stamping.

If the file is original work and includes an ownership statement then one has a strong argument for ownership as no other individual may present proof of existence of this work at an earlier point in time.

Please also have a look at this article:

http://stampd.io/cryptocurrencies-beyond-transactions/

Let me know if this clarifies your question.