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Arcana Auth SDK

Onboarding Users


Can a Web3 app use the Arcana Auth SDK only for onboarding users and disable the Arcana wallet feature altogether?

There is no way to selectively turn off the Arcana wallet features. However, if the application does not perform any blockchain transactions, the wallet feature can be disabled by setting the wallet visibility mode to false while integrating the app with the Arcana Auth SDK. In this case, the Arcana wallet will not be visible to the authenticated user as long as no blockchain transaction is triggered.

If you need to completely disable the Arcana wallet feature in the app, you can request a private build of the Arcana wallet by contacting Arcana with the use case details.

Will the Arcana Network's distributed key generation algorithm be affected if a node with a key share becomes temporarily inaccessible?

No, Arcana's ADKG algorithm can still generate the key using the key shares from the other nodes that are accessible. The algorithm is designed to tolerate a certain number of nodes being inaccessible, depending on the total number of participating nodes. For more details, see Arcana's Technical Whitepaper.

Does the authenticated user see the same wallet address if they use different authentication providers to log into a Web3 app integrated with the Arcana wallet?

Yes. This is made possible by the aggregate login feature of the Arcana Auth SDK.

For this feature to work, the user must have the same email ID registered with the different authentication providers.

Arcana Auth SDK uses the email ID to uniquely identify the user even if the user uses different social providers or the passwordless email option to log in to a Web3 app. It associates a single key for such a user which results in the user seeing the same wallet address. If the user has different email IDs associated with different social providers then each login is treated as a unique, different user and the same user will see a different wallet address when logging into the same Web3 app.

Does the authenticated user see the same wallet address across multiple Web3 applications that integrate with the Arcana Auth SDK?

Arcana Auth SDK allows Web3 app developers to tailor the wallet address experience for their users. It provides two 'Keyspace' options at the time of application registration:

  • App-Specific Keys
  • Global Keys

If a developer selects the Global Keys option, then the user gets assigned the same key across all applications that integrate with the Arcana Auth SDK and chooses the same Global Keys option. The same key means the wallet address of the user is the same across different Web3 apps that integrate with the Arcana Auth SDK. This is true across apps that use EVM-compatible chains. If two apps use global keys but one of them is on an EVM-compatible chain and the other is not, then the keys will be different across such apps. The Arcana's ADKG subsystem will assign the user different sets of keys for such apps resulting in different wallet addresses across such apps.

For more details, see app-specific vs. global keys

Does the global keys feature work across EVM-compatible and not EVM-compatible chains?

No.

The global keys feature enables an authenticated user to have the same wallet address across different Web3 apps in the Arcana ecosystem.

However, an authenticated user will see **different wallet addresses across two chains configured in a single Web3 app if one of them is EVM-compatible whereas the other is not. Also, in the case of two Web3 apps, one of which uses an EVM-compatible chain and the other that uses chains that are not EVM-compatible, the authenticated user's wallet address will be different for each app.

Why is the Global Keyspace option is not enabled if I select 'Custom Wallet UI' option during app registration in the Arcana Developer Dashboard?

If a Web3 app developer chooses the 'Custom Wallet UI' instead of the built-in Arcana wallet UI, during app registration via Arcana Developer Dashboard, only 'app-specific keys' are allowed. This is for keyspace security.

Global keys allow users to have the same private key across all the apps that integrate with the Arcana Auth SDK. With custom wallet UI, global keys are disallowed to mitigate the security risk of a malicious app hacking into user keys and gaining access to not just one but all such apps with 'Global Keys' enabled.

Are incognito/private windows in browsers and 'third-party cookies blocked' option supported by the Arcana Auth SDK?

Yes.

The Arcana wallet supports Chrome browser Incognito Window as well as Private Window in case of Safari browsers. Earlier, if third-party cookies were disabled, the built-in, plug-and-play login pop-up modal did not show up in some cases. These use cases are now addressed by the SDK.

Developers can use the canReconnect and reconnect functions of the AuthProvider to check before allowing users to reconnect whereby users do not need to re-login if they refresh the page or close the tab and re-open it again within a 30-minute window.

Does Arcana Auth SDK return a JWT token to verify users post social login?

Yes. See Arcana JWT Token for details.

For Twitter, the getUserInfo() function of the AuthProvider does not always return user's email?

You can create a Twitter account using your phone number without needing to provide an email address. If you do this, the getUserInfo() function won't give you the user's email address.

However, web3 app developers have the option to configure settings on the Twitter developer dashboard to request users' email addresses. If they do this, Arcana Auth SDK can access and retrieve the user's email through Twitter, and it will be included in the result when you use the getUserInfo() function.

Arcana wallet


How does the Arcana wallet allow app developers to manage user experience for signing blockchain transactions?

Apps can integrate with the Arcana Auth SDK to enable an embedded, non-custodial Web3 Arcana wallet for every authenticated app user.

To integrate an app, developers must register and configure the app with the Arcana network, and then install the auth package and create a new AuthProvider. While instantiating the AuthProvider developers can manage the user experience for signing blockchain transactions through the input parameter alwaysVisible. This parameter controls whether the Arcana wallet UI is automatically displayed in the application's context right after a user authenticates or it shows up only when the app triggers a blockchain transaction that requires the user's approval.

For details, see Arcana wallet visibility modes.

Does the Arcana Auth SDK set window.ethereum value in the app's context?

By default, Arcana wallet does not set the window.ethereum value in the app's context. To explicitly set this value, during the integration of the app with the Arcana wallet, when AuthProvider is instantiated, developers must specify the setWindowParameter=true. For details, see the Arcana wallet Usage Guide.

How is the Arcana wallet different from self-custodial wallets?

Arcana wallet is a non-custodial wallet. Here is how it differs from the self-custodial wallets:

Self-custodial wallets Arcana's non-custodial wallet
Users need to be responsible for and remember their passphrases. Users are not required to remember any passphrase.
Users need to manage keys themselves in case of self-custody wallets. Arcana wallet offers a sweet spot, users don't have to manage keys as in the self-custody wallet and yet their keys can be generated in a distributed manner via the Arcana wallet, a non-custodial wallet.
Users that are new to Web3 typically find self-custodial wallets very challenging to use. Arcana wallet offers a really simple Web2-like onboarding experience for new Web3 users without sacrificing security and ownership.

User Key Privacy


If Arcana is storing nothing related to user's private keys, how does Arcana provide the same wallet to a user when the user signs in for the second time?

The Arcana Auth SDK maintains a UserID -> Public Key mapping, that is how the user is identified across successive login sessions and the correct wallet is assigned for the authenticated user. This mapping is stored in the DKG nodes.

How does the Arcana Auth SDK ensure that the key shares are fetched by the correct user only?

A user can log in only after the social provider authenticates or if the user provides the OTP shared via email during passwordless onboarding. Providers share JWT/other-identifiers with Arcana Auth once the user authenticates. So unless the user themselves share their social ID / OTP, only an authenticated user will be allowed to access their key shares. The token (idToken) is verified with the DKG nodes before the key shares are sent back to the user. The token can be used only once per user login session.

Can a malicious entity reconstruct the user's private key if they get all the requisite key shares?

There are several safeguards against this and we are continuously evolving the ADKG protocol to make it more robust and fast.

One if the methods is MFA. When MFA feature is enabled, it further strengthen the security by using multiple factors used to generate private key besides the key shares. A local share is created for the user at the first login that lives on the user's device. This local key component stored on user's device is required to get the actual private key. If a user changes the device, they are validated via PIN setup during MFA or security answers before the local share is re-created on the new device.

Irrespective of whether MFA is enabled or not, the reconstruction of private key happens only once a user is authenticated by the configured social provider and the user is verified by DKG before sharing the key shares. The verification token ID changes for every user session so a malicious entity cannot reuse it. Also note that the same set of key shares is not returned for every user session by the DKG nodes. Only a random subset of shares are needed to construct the private key.

In a future version of ADKG protocol, the key shares will be periodically refreshed to safeguard against an eventuality if some of them are somehow stolen by a malicious user.


Last update: December 22, 2023 by shaloo, shalz