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Use case at hand is to show partial mobile number to user: Like 'Continue with mobile number ending with * * * * * * 1 2 3 4'

Problem is we might have last 4 digit colide due to users have choice to select last 4 digit of mobile and we are showing multiple such options so to uniquely identify option we need some other mechanism.

Options I am thinking are:

Option 1 - display 1,2 and last two digits ' 1 2 * * * * * * 3 4'

Option 2 - display 5th, 6th, last two digits ' * * * * 1 2 * * 3 4'

Option 3 - display alternate digits ' 1 * 2 * 3 * 4 * 5 *'

Option 4 - display last 4 digits ' * * * * * * 1 2 3 4'

Problem in option 4 for our country/target market there is high collision for a given user as he can choose last 4 digits.

---------EDIT------------- In my use case, in UI plan to display multiple options to customer to use one of previously done registration.

Something like this: 1. Use your account with mobile number 5647 234 4567. 2. Use your account with mobile number 7868 456 7891. 3. Use your account with mobile number 4321 321 1989.

But instead of showing full mobile number on screen we want to show tail or partial number. The question here is to what partial the best option to display it to user, so if we go by option 1 i.e. display first and last two and mask others. It will look like this.

  1. Use your account with mobile number 56** *** **67.
  2. Use your account with mobile number 78** *** **91.
  3. Use your account with mobile number 43** *** **89.
  • You forgot to mention the country. Phone numbering scheme depends on country numbering plan. What is useful and clear for one country (first two digits) may be unclear for other. And what is secure for one country may be a bad idea for other (as hidden numbers are easily suggestable). – Sergey Kirienko Jan 9 at 10:16
  • 1
    So, does the user see for example 4 options where 1 mobile phone number is his and 3 others are randomly generated or such? Can you perhaps explain the use case more in detail? – Kevin M. Jan 9 at 14:40
  • Hi Kevin M, sorry for delayed update from my end, but please have a look, I have added more description. – Ankur 13 hours ago
  • Why not have them login with a password and then give them the option to view the entire number? – RobbyReindeer 8 hours ago

Some assumptions:

a) The target country is India.

b) User can choose last four digits.

c) The possibility of the first 4 digits to be the same is very high, if the sim card/number is purchased during a certain time period/location. The first four digits identify the network operator and the telecom circle.

Now strictly going by the 4 options in the question:

Option 4 and Option 1 have high probability to fail. Among Option 2 and Option 3, Option 2 can be easier for a user since the digits at 5th and 6th positions are shown and has less chances of occurring in multiple phone numbers of a single user.

P.S. I found this question interesting since a person in my family has two phone numbers of this fashion: ABCD 3 UWXYZ and ABCD 0 UWXYZ. If that person were using this product, Option 1 and Option 4 would have failed.

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