When you add a mobile phone number to your Facebook account for two-factor authentication, Facebook uses that number in a few key ways:
- To send you authentication codes via text message when you log in from a new device.
- To help verify your identity and secure your account.
- To notify you about important security-related actions on your account.
- To allow you to more easily find friends and help others find you.
Two-factor authentication adds an extra layer of security to your Facebook account by requiring you to enter a code sent to your mobile phone when logging in from an unrecognized device. This prevents unauthorized access even if someone knows your password.
While this is the primary purpose for adding your mobile number, Facebook also leverages it for other account security and friend finding features. However, Facebook states that it does not use your number for advertising purposes or share it with third parties without your consent.
How Facebook Sends Authentication Codes
When you turn on two-factor authentication with a mobile phone number, Facebook uses that number specifically for security purposes. Here is how it works:
- When you try to log in to Facebook from a device you haven’t used before, Facebook will require a special login code.
- Facebook immediately texts the code to the mobile number you provided.
- You must then enter this code on the login screen within a short time period to access your account.
This prevents anyone else from logging in, even if they know or guess your password, since they won’t have access to the code sent to your personal mobile device.
Facebook may also occasionally send you security codes via text message if you try performing sensitive account actions from an unrecognized device. For example, if you try changing your password or recovery email from a new device, Facebook may text you a code to confirm it’s really you making the changes.
So in summary, Facebook primarily uses your mobile number to facilitate two-factor authentication by sending you temporary login codes via text message when trying to access your account.
Verifying Your Identity
In addition to two-factor login, providing your mobile phone number helps Facebook confirm your real identity and secure your account in other ways:
- If you ever forget your password, Facebook can send a password reset code to your mobile number to help you regain access.
- Adding a mobile number makes it less likely that Facebook will require additional ID verification in the future, since it links you to a real-world identity.
- If Facebook detects a suspicious login attempt, it can prompt you to confirm it was you via a texted code before allowing access.
Mobile phone numbers tend to be closely tied to individual identities, so having yours on file lets Facebook cross-reference that data when needed to verify you are who you claim to be. This provides an extra layer of protection against malicious actors trying to access your account.
If someone does manage to get into your account, having a mobile number added makes it easier for Facebook to contact you so you can regain control. Overall, associating your account with your personal mobile device helps strengthen security through improved identity verification.
Notification of Important Account Actions
Facebook may also use your mobile phone number to notify you about critical security-related events regarding your account. For example:
- If someone attempts to change your account password, Facebook will send a text to confirm if it was really you that initiated the change.
- When you enable two-factor authentication, Facebook texts you to confirm that you successfully turned on the extra security layer.
- If Facebook notices suspicious behavior like login attempts from unknown locations, it may text you a prompt to secure your account.
Getting real-time mobile notifications about important account actions provides transparency into what’s happening behind the scenes. You’ll know right away if someone else accesses your account, or if Facebook requires you to take urgent steps to lock down your security settings.
The ability to rapidly communicate security issues to your personal mobile device helps Facebook safeguard your account and inform you of risks. Receiving these critical account notifications via text message allows you to respond much faster than if Facebook only sent emails.
Finding Friends and Helping Others Find You
In addition to enhanced login security and account notifications, providing your mobile number also gives Facebook another signal to link you to real-world connections on the platform. Specifically, adding your number can help in two main ways:
- It allows Facebook to suggest friends based on who has your number saved in their contacts.
- It lets friends who have your number find your profile more easily.
For example, if a Facebook user uploads their phone contacts, Facebook can match your mobile number to connect you as friends on the platform. This helps you find people you know in real life more easily on Facebook.
Similarly, people who already have your number saved can enter it on Facebook and potentially match to your account profile. So providing your mobile number makes it easier for existing contacts to connect with you and expand your friend network.
However, Facebook states that it does not make your phone number visible on your public profile. It is only used internally to power friend recommendations and search based on user-uploaded contact data.
Some users may not feel comfortable having their mobile numbers enabled for friend finding purposes. But Facebook considers it an additional benefit of securing your account with two-factor authentication.
Data Safety and Privacy Settings
Facebook assures users that mobile phone numbers provided for two-factor authentication are kept private and not used for advertising. Here are some key facts about how Facebook handles this data:
- Your phone number is not visible on your public profile or searchable by other users.
- Facebook does not sell or share your number with third-party advertisers.
- You can control whether your number is used for friend recommendations in ad settings.
- You can remove your number at any time in your contact info settings.
Facebook also states that if you previously allowed advertisers to target ads using a hashed version of your number, turning on two-factor authentication disables that tracking. Your actual mobile number will not be accessible.
Additionally, Facebook gives you options to limit friend finding based on your number:
- Disable phone number lookups in your contact info settings.
- Turn off phone contact matching in your ad settings.
So you have granular control over how Facebook leverages your mobile number, including keeping it completely private. Facebook claims it will never sell, share or use your number for advertising purposes without your explicit permission.
However, law enforcement may request access to users’ mobile numbers in cases of legitimate criminal investigations. Facebook’s data policy states it may comply with such requests when legally required.
Removing Your Mobile Number
If you no longer wish to have your mobile phone number associated with your Facebook account, you can remove it through your account settings:
- Go to your Facebook Settings menu and select “Security and Login.”
- Under “Use Two-Factor Authentication,” click “Edit” next to the phone number you want to remove.
- Delete your phone number and save your changes.
Once removed, Facebook states it no longer uses your number for any account security, notification, or friend finding features. However, Facebook may retain your previously provided number in hashed form for legal compliance reasons.
When you delete your mobile number, two-factor authentication gets disabled. Your account will revert to only being secured by your password login. So only remove your number if you are comfortable with the reduced security and lack of login notifications.
You can add it back at any time to re-enable two-factor authentication. Just re-enter your mobile number on the Security and Login settings page and confirm the activation code Facebook texts you.
Closing Thoughts
To wrap up, here are some key points about how Facebook uses your mobile number when added for two-factor authentication:
- Primarily used for sending security codes when logging in from new devices.
- Helps verify your real identity and secure your account.
- Allows Facebook to notify you about important account actions via text.
- Lets Facebook recommend friends based on contacts who have your number.
- Kept private from other users and not used for ads.
- You control friend matching settings and can delete your number.
Overall, Facebook provides transparency into its practices around mobile numbers provided for two-factor login. The data improves account security, aids in identity verification, and powers user-friendly features like friend recommendations. However, Facebook also gives you control over how it leverages your number and the ability to remove it at any time.