It's not that special, each invoice gets assigned as hash of (invoice number + total amount + date of emission + hash of previous invoice). Besides having to send that XML file to the IRS each month with all the issued invoices, the hash also gets printed on the invoice given to the client (paper or PDF), so it gets tricky to change the past without getting caught.
It's not that special, each invoice gets assigned as hash of (invoice number + total amount + date of emission + hash of previous invoice). Besides having to send that XML file to the IRS each month with all the issued invoices, the hash also gets printed on the invoice given to the client (paper or PDF), so it gets tricky to change the past without getting caught.