Is the same decryption key used for data on the server as locally with Lastpass?

Lastpass stores the password databases encrypted on the server. Does it give a database to anyone who asks? If no, then what authentication (i.e. password) is used? I use Lastpass on multiple devices with the same master password and have not configured any other passwords. It sure would be silly if the master password is used to authenticate to the Lastpass servers when a person's password database is being retrieved.

Is there anything special about Lastpass in the sense that most servers when they do store something in ecrypted form, they know how to decrypt it e.g. a court order could compel them to do so?