The internet can be a dangerous place. We use well-established protocols, like OAuth 2.0 and OpenID Connect to communicate with each other in a well-defined and safe manner.

The problem with data sharing

In the past, sharing personal information with third-party applications online was relatively simple but posed a significant security risk. It was fairly common to share your username and password, which granted full access to your account and data. This created a vulnerability known as "Account Takeover", in which the third party could act maliciously without your knowledge or consent.

OAuth 2.0

To address this issue, the Internet Engineering Task Force (IETF) rolled out the OAuth protocol to enable third-parties to request information or perform actions on your behalf without providing access to your entire account. Today, its current iteration (OAuth 2.0 - RFC 6759) is widely used all over the internet.

OpenID Connect (OIDC)

While OAuth 2.0 provided a framework for users to delegate permission to third-party apps (authorization), the internet still lacked a standard way for federating authentication. OpenID Connect (OIDC) extended the OAuth 2.0 protocol by including a new artifact called the ID token, which serves as a proof of authentication. When using Google to log into a third-party app, you are most likely using the OIDC protocol. That app accepts Google's claims that you are who you say you are, and receives your consent to retrieve (your Google) data or take actions on your behalf!

Authorization and authentication are two key concepts in identity and access management (IAM) which are often confused with each other. A simple way to differentiate the two is to remember that:

  • Authorization is about checking for permissions - whether you have the right to perform the action you want to take

  • Authentication is about verifying your identity - whether you are who you say you are


OIDC provides a secure way for users to authenticate with and share data with third-party apps, but by default, it isn't privacy-preserving. The identity provider (Google, in the example above) knows which third-party apps you're communicating with and what data you're sending them.

To address these privacy concerns, sgID's protocol builds on top of the OIDC protocol to provide end-to-end encryption so that the identity provider does not know who you're communicating with, and the contents of the data that you're sharing with the third-party app. Read more about the sgID protocol here!

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