What is Phantom Auth?
Phantom Auth is a way to sign in anonymously to your Phantom account. It acts as a secure, privacy-first authentication factor—similar to a password or passkey. It uses public-key cryptography, the same technology that secures blockchain transactions on Solana, Ethereum, Base and Bitcoin.
With Phantom Auth, Phantom can safely store and sync your off-chain data—such as usernames, account names, and icons—while ensuring your privacy and security.
How it works
Phantom Auth operates like your wallet accounts: through self-custody and public-key cryptography.
Just as your wallet addresses are derived from your seed phrase, Phantom derives a unique authentication public key from that same seed phrase. This public key acts as a new type of sign-in method.
When you sign in to Phantom, your authentication public key signs an anonymous message. Phantom verifies this message to confirm you control the corresponding private key—without needing to know your identity. It’s the same mechanism used to sign and verify transactions on blockchain networks.
What data does Phantom sync?
When you’re signed in with Phantom Auth, Phantom can securely sync data across all your devices.
This includes:
- Your username, which is linked to your authentication public key.
- Wallet details like names, avatars, and icons for linked accounts.
For example, if you onboard to both the mobile app and the browser extension using the same seed phrase, you’ll see the same username and account avatars across both.
What can I do with my username?
Your username makes it easy to send and receive tokens and collectibles with other Phantom users. You no longer need to copy and paste long wallet addresses or worry about mistyping them.
What else can I do with Phantom Auth?
Phantom Auth lets you use your wallet like any other. You can:
- Add SOL or other tokens
- Send and receive assets
- Swap tokens
- Connect to dApps
You can also create a wallet from scratch using only a social login—no seed phrase required at onboarding.