Mobile number privacy is the protection of the phone user’s number from unwanted access. Protecting cellphone numbers has become increasingly important as smartphones and the systems they interact with, such as mobile apps, have proliferated. Although there’s a growing awareness of the need for mobile security, the need to safeguard the number itself has not been adequately addressed.
Unlike landlines, cellphones are usually associated with a single individual. Cellphone numbers are increasingly used as unique identifiers and shared with a variety of websites, applications and institutions, some of which may also share them with third parties. Cell numbers are used similarly to social security numbers by many organizations that gather them. However, unlike the SSN, organizations are not required by law to keep mobile numbers private. Furthermore, a mobile number can yield much more information than a social security number because it is connected to so many databases and the device itself is generally with the user.
Privacy experts recommend that cellphone users refrain from giving out their numbers whenever possible, and carefully consider any entity requesting a mobile number before furnishing it. There are a number of types of apps and services designed to provide mobile number privacy. Sideline, for example is an app that allows users to add a second number to give out when necessary, while keeping their original number private. Similarly, burner phone number apps and services provide people with temporary second numbers that can be used in situations where it's not necessary for the requester to have a permanent number.