The DSB proposes the following convention:
Mobile phone numbers may be used as CDR user identifiers but only if they are uniquely registered and verified to a single eligible CDR consumer.
This convention is supported by the following conventions:
- CDS-DC-0014: "Align CDR channel experiences to existing digital channel experiences".
- CDS-DC-0015: "The CDR User Identifier should be familiar and consistent with existing digital channels"
- CDS-DC-0016: "CDR User Identifiers need to uniquely identify a single customer of the data holder"
- CDS-DC-0017: "Verifying Mobile Phone Numbers for use as CDR User Identifiers"
These days, mobile phone numbers are ubiquitous and people generally retain the same number for a long period of time, e.g. a decade or more. With the ability to port mobile phone numbers between carriers and plans, people can retain the same phone number regardless of the mobile phone plan they choose.
Compared to other user identifiers (such as customer IDs issued and controlled by the data holder) recall is also higher and they tend to be easier to type. This means that mobile phone numbers are an increasingly popular option as a user identifier.
A mobile phone number can be considered a valid user identifier if it uniquely identifies a single eligible CDR consumer and has universal application to the data holder's customer base. Further, the mobile phone number needs to be verified and use within the CDR is reasonable so long as the customer can use their mobile phone number in the data holder's existing digital channels for login and authentication services.