Separating email addresses, phone numbers, and recovery methods

When creating an anonymous account, if you look only at the display name or profile, you miss important parts.

Email address, phone number, recovery account, two-factor authentication, contact syncing. These may not be visible from the outside. However, inside the service, they become strong identifiers.

If you use an email address or phone number tied to your real-name identity for an anonymous account, account separation becomes weaker. Even if the account looks anonymous from the outside, registration information and recovery methods connect it with the real-name side.

This article lays out how to separate email, phone numbers, and recovery methods before creating an anonymous account.

Registration information becomes a strong identifier

For anonymity, looking only at the post body or IP address is not enough.

Information used when registering an account is also important. Email addresses, phone numbers, recovery email addresses, devices used for two-factor authentication, and contact syncing are used by services to manage users.

Registration information may not be displayed in the profile. However, invisible does not mean safe.

Separate email addresses

For anonymous accounts, the basic rule is not to use a real-name email address.

Your everyday email address is connected to your real name, workplace, school, past accounts, payments, cloud services, and contacts. If you use that email for an anonymous account, a strong correlation is created inside the service.

Pay attention to the email address string too. If it contains a real name, birthday, old handle, game ID, workplace name, or region name, it can also become a clue if it becomes visible from the outside.

Even when creating an email address for anonymous use, avoid mixing that email itself with your everyday real-name environment.

Separate phone numbers

A phone number may become an even stronger identifier than an email address.

Many services use phone numbers for SMS authentication, identity verification, abuse prevention, and account recovery. If you use the same phone number for a real-name account and an anonymous account, it gives the service a reason to treat them as the same user internally.

Phone numbers also relate to contact syncing. If a phone number saved in an acquaintance's smartphone becomes connected to an account on a service, it may affect recommendation displays or suggested acquaintances.

When using a service that requires a phone number for anonymous purposes, review the threat model at that point. A service that requires a number may be unsuitable for anonymous operation.

Separate recovery methods too

For anonymous accounts, pay attention not only to the email address or phone number used at registration, but also to recovery methods.

Recovery email addresses, backup codes, authenticator apps, backup phone numbers, and linked accounts are often not visible from the outside. However, for account management, they become very strong connections.

For example, if you set a real-name email as the recovery destination for an anonymous account, it may look anonymous during ordinary use, but the recovery route connects it with the real-name environment.

Recovery methods become a problem after you have forgotten about them. If they are not separated at the beginning, they become difficult to fix later.

Avoid contact syncing

Smartphone apps sometimes request access to contacts.

If you allow contact syncing with an anonymous account, it may connect you with family, friends, workplace contacts, or school contacts. It may also cause the account to be shown to those people as an "account you may know."

In anonymous operation, avoid contact syncing as a general rule. Particular care is needed when using an anonymous account on a real-name smartphone.

For anonymity, it is also important not to involve people connected to you, not just yourself.

Checks before creating an account

Before creating an anonymous account, check the registration information.

If any item remains that you cannot judge here, it is better not to register immediately. Registration information may not be fully removable later.

Cautions when changing information

If you have already created an anonymous account, you may later want to change the email address or phone number.

Changing it may be effective. However, the information before the change may remain as history inside the service. The change process itself may also create new traces, such as a notification sent to a real-name email, logging in from an everyday device, or being asked for identity verification.

When changing information, it is important not to operate in a hurry. Check which environment you will log in from, where notifications will arrive, and what will remain after the change before you act.

Summary

For anonymous accounts, you need to separate not only the display name and profile, but also registration information.

Email addresses, phone numbers, recovery email addresses, two-factor authentication, and contact syncing become strong identifiers inside the service even when they are not visible from the outside.

If you use a real-name email or everyday phone number for an anonymous account, account separation becomes weaker. The same applies to recovery methods and linked logins.

In anonymous operation, separate registration information from the start. Use a dedicated email, choose services that require a phone number carefully, and avoid mixing recovery destinations and storage locations with the real-name environment.

Anonymity is greatly affected from the registration stage before posting begins.

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