MPC key shares are used for signing ECDSA & EDDSA transactions that originate in the Vault for all blockchain protocols. Fireblocks uses MPC technology to separate the private key into three key shares that are stored in three different locations. The signing process happens without re-assembling the key, mitigating the risk of a single point of failure.
If a user's role has signing permissions, their MPC key shares must be approved and generated by the workspace owner. MPC key shares are generated separately for each user and each workspace. Your share is stored on your mobile device.
If your MPC key share has not been approved, you will not be able to withdraw from any Vault account or sign transactions submitted by a different user in your workspace. You will be able to sign into the console and depending on your user role, view all available accounts and settings, send transactions from third party connections, make and approve workspace changes, submit and approve new connections.