Social logins

Documentation Index

Fetch the complete documentation index at: https://docs.0xkey.io/llms.txt

Use this file to discover all available pages before exploring further.

Similar to email auth, social login authentication is ideal for users who prefer not to manage API keys or passkeys directly. This makes it particularly well-suited for onboarding users who are comfortable with traditional web2-style accounts but may be unfamiliar with cryptographic keys and credentials. An example implementing social login authentication for an organization can be found in our SDK repo here.

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Types of social login providers

0xkey supports two different types of Social Login Providers:

1. OIDC Providers (Google, Apple, Auth0, Cognito…) These providers issue your app an OIDC ID Token identifying an end-user, which can subsequently be passed to 0xkey as a means of authentication.
2. OAuth 2.0-Only Providers (X/Twitter, Discord…) These providers do not issue OIDC ID Tokens themselves, and instead provide only bare-bones OAuth 2.0. To work around this limitation, 0xkey runs the OAuth 2.0 Authorization Code + PKCE flow, calls the provider’s who-am-I endpoint using your app’s credentials, and then uses the returned user data to issue a short-lived OIDC ID token. In effect, 0xkey acts as an “OIDC Wrapper” for these OAuth 2.0 Services.

While the backend flows associated with these two types of Providers differ upstream of OIDC ID Token generation, they converge at that point and have no downstream differences. In both cases, the goal is to get an OIDC ID Token identifying the end user.

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Social login provider types - comparison

The table below can be helpful in understanding the similarities and differences between the two types of Social Login Providers that 0xkey supports:

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Roles and responsibilities

• 0xkey: Runs verifiable infrastructure to create credentials, verify OIDC tokens and, in the case of OAuth 2.0-Only Providers, issue them as well.
• Parent: That’s you! For the rest of this guide we’ll assume you, the reader, are a 0xkey customer. We assume that you have:
  • An existing 0xkey organization (we’ll refer to this organization as “the parent organization”)
  • A web application frontend (we’ll refer to this as just “app” or “web app”)
  • A backend able to sign and POST 0xkey activities (“backend” or “parent backend”)
• End-User: The end-user is a user of your web app. They have an account with Google.
• OIDC Provider: A provider able to authenticate your End-Users and provide OIDC tokens as proof. We’ll use Google as an example.
• OAuth 2.0-Only Provider: A provider of OAuth 2.0-based Authorization, for which 0xkey is able to act as an “OIDC Wrapper”.

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Authentication sequence diagrams

The sequence diagrams below display the differing flows for the two types of Social Login Providers.

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OIDC provider

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OAuth 2.0-only provider

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What does 0xkey use from the OIDC tokens to prove identity?

0xkey parses and validates the following fields from the OIDC token to confirm the user’s identity:

• issuer (iss) – The OAuth provider that issued the token (e.g., https://accounts.google.com)
• audience (aud) – The OAuth app’s client ID
• subject (sub) – The unique identifier for the user in the OAuth provider’s system

Note:
Some OAuth providers (like Google) encourage you to register separate client IDs for each platform (e.g., web, iOS, Android). However, as discussed above, in the 0xkey flow the aud claim from the OIDC token is used as part of how sub-organizations are identified. If a user logs in on one platform using the web client ID, and then later logs in on another platform using a different iOS client ID, the two tokens will have different aud values. Because of this, 0xkey will not consider them the same identity. To ensure users are recognized consistently across platforms, you must use the same OAuth client ID everywhere. In most cases, this means using your web client ID for web, iOS, and Android flows.

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OIDC token verification

All OIDC tokens are verified inside of 0xkey’s secure enclaves. We’ve designed a new secure enclave to fetch TLS content securely and bring non-repudiation on top of TLS content: our TLS fetcher returns a URL and the fetched content, signed by the TLS fetcher’s quorum key. By trusting the TLS fetcher quorum key, other 0xkey enclaves can bring TLS-fetched data into their computation safely. Verifying OIDC token is the first computation which requires this! To verify an OIDC token, other 0xkey enclaves receive the OIDC token as well as:

• the signed content of the issuer’s OpenId configuration. OpenId configuration must be hosted under /.well-known/openid-configuration for each domain. For Google for example, the issuer configuration is at accounts.google.com/.well-known/openid-configuration. This JSON document contains, among other thing, a jwksUri key. The value for this key is a URL hosting the list of currently-valid OIDC token signers.
• the signed content of the issuer’s jwksUri (e.g., for Google, the jwksUri is googleapis.com/oauth2/v3/cert). This is a list of public keys against which the secure enclave can verify tokens. Note: these public keys rotate periodically (every ~6hrs), hence it’s not possible to hardcode these public keys in our secure enclave code directly. We have to fetch them dynamically!

With all of that, an enclave can independently verify an OIDC token without making outbound requests. Once the token is parsed and considered authentic, our enclaves match the iss, aud and sub attributes against the registered OAuth providers on the 0xkey sub-organization. We also check exp to make sure the OIDC token is not expired, and the nonce attribute (see next section).

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Nonce restrictions in OIDC tokens

Our OAUTH_LOGIN activity requires 2 parameters minimum:

• oidcToken: the base64 OIDC token
• publicKey: the client-side public key generated by the user

In order to prevent OIDC tokens from being used against multiple public keys, our enclaves parse the OIDC token and, as part of the validation logic, enforce that the nonce claim is set to sha256(publicKey). For example, if the public key is 0394e549c71fa99dd5cf752fba623090be314949b74e4cdf7ca72031dd638e281a, our enclaves expect the OIDC token nonce to be 1663bba492a323085b13895634a3618792c4ec6896f3c34ef3c26396df22ef82. This restriction only applies during authentication (OAUTH activity). Registration via CREATE_OAUTH_PROVIDER and CREATE_SUB_ORGANIZATION activities is not affected since these activities do not accept a publicKey and do not return encrypted credentials as a result. If your OAuth provider does not allow you to customize nonce claims, 0xkey also accepts and validates tknonce claims. This is an alternative claim that will be considered. Only one of (nonce, tknonce) needs to be set to sha256(publicKey); not both.

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OAuth vs. OIDC

OAuth2.0 is a separate protocol from OIDC, with distinct goals:

• “OAuth2.0” is an authorization framework
• “OIDC” is an authentication framework

We chose to name this feature “OAuth” because of the term familiarity: most 0xkey customers will have to setup an “OAuth” app with Google, and the user experience is often referred to as “OAuth” flows regardless of the protocol underneath.

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OIDC providers

Below, some details and pointers about specific providers we’ve worked with before. If yours isn’t listed below it does not mean it can’t be supported: any OIDC provider should work with 0xkey’s OAuth.

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Google

This provider is extensively tested and supported. We’ve integrated it in our demo wallet (hosted at https://wallet.tx.xyz), along with Apple and Facebook: The code is open-source, feel free to check it out for reference. The exact line where the OAuth component is loaded is here: ui/src/screens/LandingScreen.tsx. The main documentation for Google OIDC is available here.

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Apple

Apple integration is also extensively tested and supported, and is integrated into our demo wallet (hosted at https://wallet.tx.xyz). The code provides an example component as well as an example redirect handler. Documentation for Apple OIDC can be found here.

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Facebook

Facebook OIDC requires a manual flow with PFKE (Proof for Key Exchange). This flow requires a few extra steps compared with Apple or Google. Specifically:

• You will need to generate a code verifier that can either be recalled (e.g. from a database) or reassembled in a later request.
• You will need to provide a code challenge as a parameter of the OAuth redirect that is either the code verifier itself or the hash of the code verifier.
• Instead of receiving the OIDC token after the OAuth flow, you will receive an auth code that must be exchanged for an OIDC token in a subsequent request. The code verifier and your app’s ID are also required in this exchange.

In our example demo wallet, we opt to avoid using a database in the authentication process and instead generate our verification code serverside using the hash of a nonce and a secret salt value. The nonce is then passed to and returned from the Facebook API as a state parameter (see the API spec for details). Finally, the server reconstructs the verification code by re-hashing the nonce and the the salt. The full flow is displayed below: Code for the redirect component, OAuth callback, and code exchange are all available in the example wallet repo. If you prefer to use a database such as Redis instead of reassembling the verification code, you can store the verification code and retrieve it in the exchange stage using a lookup key either passed as state or stored in local browser storage.

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Auth0

This provider was tested successfully and offers a wide range of authentication factors and integration. For example, Auth0 can wrap Twitter’s auth or any other “Social Connection”. In the testing process we discovered that Auth0 admins can manage users freely. Be careful about who can and can’t access your Auth0 account: Auth0’s management APIs allow for account merging. Specifically, anyone with a users:update scope token can call this endpoint to arbitrarily link an identity. For example, if a Google-authenticated user (OIDC token sub claim: google-oauth2|118121659617646047510) gets merged into a Twitter-authenticated user (OIDC token sub claim: twitter|47169608), the OIDC token obtained by logging in through Google post-merge will be twitter|47169608. This can be surprising and lead to account takeover if an Auth0 admin is malicious. This is documented in Auth0’s own docs, here.

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AWS Cognito

Amazon Cognito supports the standard OIDC nonce parameter — you can supply a custom nonce value in the /oauth2/authorize request and Cognito will include it in the resulting ID token (as per AWS documentation).

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Social linking

Social linking is the concept of automatically linking an email address to a 0xkey user by authenticating with a social provider. This allows an end-user to authenticate with the social provider, or a matching email address. Currently, we only allow automatic linking for Google social logins. The cases are as follows:

1. The end-user authenticates with Google. Their email address is automatically linked to their authentication methods and considered “verified,” allowing them to log in with email OTP or email auth in the future.
2. The end-user authenticates with a Google email address (e.g., @gmail.com) via email OTP or email auth. If they later authenticate with Google, the Google OIDC provider will automatically be added as a valid login method, provided the email matches.
3. The end-user has existing non-Google authentication methods (e.g. phone number, passkeys, etc.) and later adds Google OIDC as a login method (via CREATE_OAUTH_PROVIDERS). The email address in the Google account will be automatically marked as “verified” and linked to the existing user.

For more information on how to implement social linking, see the social linking code example.

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Setup for OAuth 2.0-only providers

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Setting up X/Twitter

Navigate to the X developer portal and create/setup your app. In the Keys and Tokens section, you’ll need to save your Client ID and Client Secret so that these values can be uploaded to 0xkey’s servers:

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Required scopes

In order for 0xkey to access the /2/users/me endpoint, the following scopes must be set during Authorization:

• tweet.read
• user.read

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Setting up Discord

Navigate to the Discord developer portal and create/setup your app. In the General Information section, you’ll need to save your Client ID and Client Secret so that these values can be uploaded to 0xkey’s servers:

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Required scopes

In order for 0xkey to access the /api/users/@me endpoint, the following scopes must be set during Authorization:

• identify
• email

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Client secret upload

For every OAuth 2.0-Only Social Provider that you wish to integrate with, you must upload the Client ID and Client Secret issued by that Provider to 0xkey’s Servers. In order to protect these sensitive credentials, they will be encrypted to the Quorum Key of the TLS Fetcher enclave, which ensures they cannot be accessed outside of that environment. You can upload these credentials through the 0xkey Dashboard. In the Wallet Kit section of the dashboard, head to the Socials tab and click Add provider. Select the provider you want to add from the dropdown, and fill in the required fields. You can find these values in the provider’s developer console. Any secrets will automatically be encrypted before uploading to 0xkey. Once uploaded, you can then use the Credential Id from the table shown to make requests to the OAUTH2_AUTHENTICATE activity. You can also see the example here demonstrating how to encrypt and upload your client secrets using our SDK instead.

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Returning the encrypted bearer token

When using OAuth 2.0-Only Social Providers, it is also possible to have the bearer token returned by the OAuth2Authenticate endpoint, which can be useful if you would like your app to have additional integrations involving this Social Provider. In order to guarantee the secure transfer of the bearer token, it must be encrypted to a P256 Encryption Key inside our secure enclave, returned to the caller, and then finally decrypted. Therefore, the return of the encrypted bearer token is dependent on the caller providing an optional bearerTokenTargetPublicKey parameter in the request to OAuth2Authenticate. An example demonstrating this flow can be seen here.