Mobile application without direct authorization \ registration

Question

UX \ UI professionals. The question connects both the user experience and data security.

We are going to build the app, where the user is going to pay for the services.

He should enter his email, phone and info before the purchasing and we're going not to implement the authorization within the app.

So, after the user enters his email, we'll check either his account exist or no. If no, we'll create, if not - authorize, but in the background, not showing this to him.

We need to authorize him only to check his purchases history, data for the credit card won't be saved by us.

How do you think, is it preferable method? What aftergrowths it can cause? Thank you.

Answer 1

That solution sounds insecure: the user could enter the email address of anyone who happens to be registered. That user would then presumably be able to view the purchase history belonging to that email address. To close that security hole, you need to send an email to the owner of the account. The email should contain either a short random security code or a link with a long random security code. Only when your app receives the security code can you be certain that the user owns that email address.

Answer 2

So, after the user enters his email, we'll check either his account exist or no. If no, we'll create, if not - authorize, but in the background, not showing this to him.

After the email verification returns a "does not exist" will you require the user to create a password to continue the set up. Once the user has done this a background email should be triggered to the user email registering his or hers interest in your product. On completion of the sales proccess should you send a welcome and recipt of sale email.

If the email does exist you will need the user to login using that email and a password. No email is triggered except a recipt of the sales purchase is complete.

If a user drops off before the purchase, will the email they used be stored and let the user continue the sale at a later date?

My only concern is without a verification email anyone can put anyones email in and create an account. Obviously they cannot use another persons financial credentials but without email verification you are leaving the system open to problems.