Two-factor authentication: password + email?

Question

Programming

Hi!
There is a task of implementing two-factor authentication in a term paper.
Standard set: password + sms does not work: how will I send sms ...
Will it be considered if I do: password + code to email?
What other "free" ways to implement two-factor authentication are there?
Thank you in advance!

Answer 1

do it like on any dropbox with Google: password + one-time code generated by a special application.

Answer 2

Previously, some operators provided a gate service that allowed you to send SMS by sending email to the gate address. Then the gate was made not from emoyl, but from a web page with captcha, because they spammed like that. I don’t know if everyone closed the gates or did someone still have such an opportunity? Surely there is, but most likely for money (contract). After all, there are all sorts of shops-banks send. Ask your telecom operators if this is possible and under what conditions.
Another option for two-factor authentication is an application on a smartphone that generates codes that change every 30 seconds according to the "salt" (or "seed") given to the user by the site, at any time, according to the algorithm and this "salt", the current key is calculated and compared user input with calculated value.

Answer 3

Do it on OpenOTP, there are a lot of plugins and code delivery options for it. Make several delivery options at once and the teacher will be happy.