The Risks of Single Sign-On: Why 'Sign in with Google' is a Double-Edged Sword
The convenience of "Sign in with Google" (SSO) Single Sign-On is undeniable. With a single click, you can create accounts on dozens of third-party services. However, this convenience comes at a cost: you are essentially outsourcing your digital identity to a single point of failure. This creates a critical vulnerability where losing access to your Google account can lead to a system-wide lockout from your entire digital life.
The Single Point of Failure
When you use Google as your identity provider (IdP), you are not creating a separate account for the same service; you are trusting Google to vouch for your identity. If your Google account is banned, disabled, or hacked, you lose access to every service that relies on that SSO connection.
One of the primary concerns raised by the community is the lack of human support. As noted by user @CM30, the difficulty of recovering an account is often a nightmare:
"Google's lack of support is notorious... any YouTuber who gets their account hacked is reduced to begging for help on Twitter, since there seems to be no-one at the company able to help directly if contacted from the site itself."
This lack of transparency and algorithmic banning processes can leave users in a limbo state where they have no clear path to recovery, effectively erasing their digital presence across multiple platforms simultaneously.
Custom Domains vs. Gmail
A critical distinction must be made between using a @gmail.com address and using a custom domain via Google Workspace. The risk profile changes significantly depending on which you are using.
The Gmail Risk
If you use a @gmail.com address, you are essentially renting your identity. If Google bans your account, you have no way to migrate your identity to another provider. Your email address—the primary identifier for almost every online service—is gone.
The Custom Domain Advantage
For those using custom domains (e.g., me@mydomain.com), the risk is mitigated. As user @nrvn explains, SSO typically binds to the email address as the primary identifier. This means if you move your email hosting to another provider, you can often still regain access to your services if the provider supports password resets or alternative authentication methods.
"SSO binds your email address as the primary account idenitifier in all known to me services. Does not matter what IDP you use to “sign in with”. I find this twitter thread misleading. Unless the affected account was using @gmail.com as their primary identity."
The Dilemma of Alternatives
While the risk of centralized login is clear, the alternatives often present their own set of challenges. User @Jotalea points out that moving to a custom domain and self-hosting is not a viable solution for everyone:
"now what? sure i could buy a custom domain and host an email server on it, but now now i have to care about server maintenance, SSL, and yearly payments... just as Google can, the hosting provider can block my account, or even go down itself."
Furthermore, there is a security risk associated with custom domains: if a domain expires and is not renewed, a new owner of that domain can potentially reset passwords for services linked to that email address, creating a a new vector for account takeover.
Conclusion: Assessing the Risk
Digital identity management is an overall balance of risk assessment. For those whose digital presence is critical, the rule of thumb is to avoid relying on a sole provider for authentication. Diversify your authentication methods, use custom domains for critical accounts, and use backup tools like Google Takeout to export your data periodically. The goal is to avoid a single point of failure that ensuring your digital identity remains under your own control.