What does this service do?
Who needs this service?
What is the hash of the file?
What guarantees our service?
What is the "Validity period"?
How to verify a file?
How to prove authorship?
Is the file stored in the blockchain?
Who sees my file?
Is it possible to determine by the hash sum what the file contains?
Is it possible to sign the same file twice?
And how is the authorship protected then, if anyone can notarize the file any number of times?
How else can legally copyright be protected?