Bitfrost is the security design specification for the

OLPC XO The OLPC XO (formerly known as $100 Laptop, Children's Machine, 2B1) is a low cost laptop computer intended to be distributed to children in developing countries around the world, to provide them with access to knowledge, and opportunities to ...

, a low cost laptop intended for children in developing countries and developed by the One Laptop Per Child (OLPC) project. Bitfrost's main architect is Ivan Krstić. The first public specification was made available in February 2007.

Bitfrost architecture

Passwords

password A password, sometimes called a passcode (for example in Apple devices), is secret data, typically a string of characters, usually used to confirm a user's identity. Traditionally, passwords were expected to be memorized, but the large number of ...

s are required to access or use the computer.

System of rights

Every program, when first installed, requests certain bundles of rights, for instance "accessing the camera", or "accessing the internet". The system keeps track of these rights, and the program is later executed in an environment which makes only the requested resources available. The implementation is not specified by Bitfrost, but dynamic creation of security contexts is required. The first implementation was based on

vserver Linux-VServer is a virtual private server implementation that was created by adding operating system-level virtualization capabilities to the Linux kernel. It is developed and distributed as open-source software. Details The project was started ...

, the second and current implementation is based on user IDs and group IDs (/etc/password is edited when an activity is started), and a future implementation might involve

SE Linux Security-Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including mandatory access controls (MAC). SELinux is a set of kernel modifications and user-space t ...

or some other technology. By default, the system denies certain combinations of rights; for instance, a program would not be granted both the right to access the camera and to access the internet. Anybody can write and distribute programs that request allowable right combinations. Programs that require normally unapproved right combinations need a

cryptographic signature A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature, where the prerequisites are satisfied, gives a recipient very high confidence that the message was created b ...

by some authority. The laptop's user can use the built-in

security" \n\n\nsecurity.txt is a proposed standard for websites' security information that is meant to allow security researchers to easily report security vulnerabilities. The standard prescribes a text file called \"security.txt\" in the well known locat ...

panel to grant additional rights to any application.

Modifying the system

The users can modify the laptop's

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

, a special version of

Fedora Linux Fedora Linux is a Linux distribution developed by the Fedora Project. Fedora contains software distributed under various free and open-source licenses and aims to be on the leading edge of open-source technologies. Fedora is the upstream source ...

running the new Sugar

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inst ...

and operating on top of

Open Firmware Open Firmware is a standard defining the interfaces of a computer firmware system, formerly endorsed by the Institute of Electrical and Electronics Engineers (IEEE). It originated at Sun Microsystems, where it was known as OpenBoot, and has bee ...

. The original system remains available in the background and can be restored. By acquiring a developer key from a central location, a user may even modify the background copy of the system and many aspects of the BIOS. Such a developer key is only given out after a waiting period (so that theft of the machine can be reported in time) and is only valid for one particular machine.

Theft-prevention leases

The laptops request a new "lease" from a central network server once a day. These leases come with an expiry time (typically a month), and the laptop stops functioning if all its leases have expired. Leases can also be given out from local school servers or via a portable

USB Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...

device. Laptops that have been registered as

stolen Stolen may refer to: * ''Stolen'' (2009 Australian film), a 2009 Australian film * ''Stolen'' (2009 American film), a 2009 American film * ''Stolen: The Baby Kahu Story'' (2010 film), a film based on the real life kidnapping of baby Kahu Durie ...

cannot acquire a new lease. The deploying country decides whether this lease system is used and sets the lease expiry time.

Microphone and camera

The laptop's built-in

camera A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a ...

and

microphone A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and publ ...

are hard-wired to LEDs, so that the user always knows when they are operating. This cannot be switched off by software.

Privacy concerns

Len Sassaman Leonard Harris Sassaman (April 9, 1980 – July 3, 2011) was an American technologist, information privacy advocate, and the maintainer of the Mixmaster anonymous remailer code and operator of the ''randseed'' remailer. Much of his career gravita ...

, a computer security researcher at the Catholic University of Leuven in

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

and his colleague

Meredith Patterson Meredith Ann Patterson (born November 24, 1975) is an American musical theatre and television actress. She is best known for her Broadway performances such as Peggy Sawyer in 2001 Revival of "42nd Street", '' The Boy Friend'' and '' White Christ ...

at the

University of Iowa The University of Iowa (UI, U of I, UIowa, or simply Iowa) is a public research university in Iowa City, Iowa, United States. Founded in 1847, it is the oldest and largest university in the state. The University of Iowa is organized into 12 col ...

in Iowa City claim that the Bitfrost system has inadvertently become a possible tool for unscrupulous governments or government agencies to definitively trace the source of digital information and communications that originated on the laptops. This is a potentially serious issue as many of the countries which have the laptops have governments with questionable human rights records.

Notes

* The specification itself mentions that the name "Bitfrost" is a play on the Norse mythology concept of Bifröst, the bridge between the world of mortals and the realm of Gods. According to the

Prose Edda The ''Prose Edda'', also known as the ''Younger Edda'', ''Snorri's Edda'' ( is, Snorra Edda) or, historically, simply as ''Edda'', is an Old Norse textbook written in Iceland during the early 13th century. The work is often assumed to have been t ...

, the bridge was built to be strong, yet it will eventually be broken; the bridge is an early recognition of the idea that there's no such thing as a perfect security system.

References

{{Reflist

External links

Ivan Krstić's homepage
* OLPC Wiki: Bitfrost
Bitfrost specification
version Draft-19 - release 1, 7 February 2007

Wired News, 7 February 2007
Making antivirus software obsolete
- Technology Review magazine recognized Ivan Krstić, Bitfrost's main architect, as one of the world's top innovators under the age of 35 (Krstić was 21 at the time of publication) for his work on the system. One Laptop per Child Cryptographic software