Hash for Invoice-Number

Hello,

i would love to "hide" my invoice number. By law I need to give each invoice a dedicated (ascending) number. However, this leads to the fact that each customer knows how many invoices i have sent (this year).

I therefore came up with the solution to hash my invoice number. Would it be possible to include this?

E.g. on the invoice settings page you can choose an PHP function (algorithm) to allow hashing before the invoice number gets calculated.

![image](

PS.: I am using InvoiceNinja for three years now and it totally fits into my billing workflow! Very cool :)