Portal lets you securely back up your users’ MPC wallets so they can recover their wallets even if their device is lost or damaged. By default, Portal encrypts and stores both backup shares (“Portal-Managed Backups”):
The client backup share is encrypted on the user’s device, with the encryption key stored using their chosen backup method (Google Drive, iCloud, Password, or Passkey). The encrypted share is then stored by Portal.
The custodian backup share is encrypted and stored by Portal, with the encryption key stored in our KMS infrastructure.
By default, Portal manages storing both the encrypted client backup share and the custodian backup share for you. If you prefer to store and manage the backup shares in your own infrastructure instead of using Portal-Managed Backups, see our Self-Managed Backups guide.
Both the client backup share and the custodian backup share are necessary to recover a Portal wallet.