If you do bookkeeping with pen and paper, you can throw away the page and replace it with a new piece of paper. The security mechanism is out of band - you kee

If you do bookkeeping with pen and paper, you can throw away the page and replace it with a new piece of paper. The security mechanism is out of band - you keep the pages secure, and you also reconcile / audit your accounts with those of your bank, suppliers, customers, etc - it's never 100% within the medium of the accounts themselves.