This Contribution is part of the Utopian Registration-Project.
The goal for the Utopian Registration is, to allow People who are new to STEEM to create an Utopian ( STEEM ) - Account through Utopian itself (and not how it is currently handled, through STEEMIT).
And one of the steps for that is, for the user to confirm a phone-number via SMS.
In this Contribution-Post I'll take you through the changes I've made to the backend.
You can find the pull-request here: Pull Request
I've already created a Contribution Post about the SMS-Verification changes that I've added to the frontend in this Post: https://utopian.io/utopian-io/@therealwolf/utopian-registration-frontend-sms-verification
But the important part is the logic behind the interface, which is exactly what I'm now going to talk about.
The Registration Frontend allows Users to login via their favourite Social-Media (currently supported are Github, Facebook and later also LinkedIn). While some accounts have already a level of verification which is enough to allow the user to create an account, some accounts are simply too new or due to other reasons not enough to use as verification. That's where SMS-Verification comes into play.
However, another reason for SMS-Verification is also the ability to recover the password - in addition with the last digits of the recent password.
The goal for the SMS-Verification was to use a provider that is both fast, secure and not that expensive - as for example twilio.
That's why I went with NEXMO.
The logic behind the Verification is to create a random combination of letters and numbers with a length of 4 and sending it with an SMS to the Number, which was entered by the User.
If the User has successfully entered the code, the Account will be verified by SMS and the User is then able to create the Account.
One of the security measures that I build in is the maximum amount of 3 SMS that can be send. If the User is trying to send a 4th message, he / she will be shown an error saying that the SMS-Limit has been reached and that he / she should contact the moderators on discord.
Additionally, NEXMO comes with an automatic SPAM- & Blacklist, which should help save 
The next step is to create the STEEM Account itself and then create and link this account to the Utopian-Database Object.
