The laptops include an anti-theft system which can, optionally, require each laptop to periodically make contact with a server to renew its cryptographic lease token. If the cryptographic lease expires before the server is contacted, the laptop will be locked until a new token is provided. The contact may be to a country-specific server over a network or to a local, school-level server that has been manually loaded with cryptographic "lease" tokens that enable a laptop to run for days or even months between contacts. Cryptographic lease tokens can be supplied on a USB flash drive for non-networked schools. The mass production laptops are also tivoized, disallowing installation of additional software or replacement of the operating system. Users interested in development need to obtain the unlocking key separately (most developer laptops for Western users already come unlocked). It is claimed that locking prevents unintentional bricking and is part of the anti-theft system.