Internet Identity gives each app a different identifier for the same person

Connect the same crypto wallet to ten apps and all ten see the same address. That shared address is a trail anyone can piece together into a single profile, quietly eroding user privacy across the decentralized web.

Internet Identity, built by @dfinity on the Internet Computer, takes a different approach. Rather than relying on a wallet address, a password, or a seed phrase, it authenticates users through a passkey: the fingerprint scanner or face unlock already built into a phone, or a dedicated hardware key such as a YubiKey.

One Person, Many Identities

The core privacy mechanism is unlinkability. Users sign in with passkeys instead of passwords, and each user receives a unique principal per frontend origin, preventing cross-app tracking. In practice, that means two apps sharing the same underlying user have no way to confirm that fact. The separate identities of a single user cannot be related merely based on their public key or principal IDs, to impede user tracking.

Unlinkability is provided across apps. Because there is no central authority issuing and managing identities, two different dapps creating sessions with a single Internet Identity cannot distinguish whether it is the same underlying user or not.

Those per-app identities also remain stable as users switch devices, and the app itself never sees the underlying identity number. Discoverable passkeys mean users no longer need to remember or store an identity number.

No Password, No Seed Phrase

Internet Identity uses the WebAuthn standard built into browsers to create cryptographic material that is then used to identify the user. Hardware keys such as a YubiKey can serve as the passkey, with the cryptographic material typically stored in the browser or by the OS, except when a dedicated hardware passkey is used.

No personal data is shared with Internet Identity or the dapps using Internet Identity. The system has also expanded its sign-in options over time: Google, Apple, and Microsoft email accounts are now integrated as an alternative authentication option alongside passkeys, broadening access for users not yet comfortable with hardware keys.

For the broader crypto ecosystem, the model presents a meaningful contrast to standard wallet-based authentication, where a single public address functions as a persistent, public identity across every app it touches. Internet Identity's per-app principal design limits that exposure without requiring users to manage multiple wallets or complex key infrastructure.

Sources:
Internet Identity - ICP Developer Docs
Internet Identity Specification - DFINITY GitHub
Internet Identity 2.0 - DFINITY Support