How to make budgetary two-factor authorization (via SMS)?

Question

SMS

There is apache under Windows, 1C 8.3 web application rotates on it, it’s not secure to expose it outside with 1C authorization.
I would like to make two-factor authorization via sms as simple as possible. I found options using swivel, but this thing is very cool, I need a less expensive option in terms of money, who can tell me what to assemble or help implement it?

Answer 1

What is stopping you from upgrading your current authorization to two-factor? Bind a phone number to each user, send a six-digit code to this number during authorization, and that's it.
For such purposes I use www.smspilot.ru