Capabilities and Access Control Lists
Within computer systems, two security models capable of enforcing privilege separation are access control lists (ACLs) and capability-based security. The semantics of ACLs have been proven to be insecure in many situations, for example, the confused deputy problem. It has also been shown that the promise of ACLs of giving access to an object to only one person can never be guaranteed in practice. Both of these problems are resolved by capabilities. This does not mean practical flaws exist in all ACL-based systems, but only that the designers of certain utilities must take responsibility to ensure that they do not introduce flaws.
Capabilities have been mostly restricted to research operating systems and commercial OSs still use ACLs. Capabilities can, however, also be implemented at the language level, leading to a style of programming that is essentially a refinement of standard object-oriented design. An open source project in the area is the E language.
The most secure computers are those not connected to the Internet and shielded from any interference. In the real world, the most secure systems are operating systems where security is not an add-on.
Read more about this topic: Computer Security
Famous quotes containing the words capabilities, access, control and/or lists:
“I maintain that I have been a Negro three times—a Negro baby, a Negro girl and a Negro woman. Still, if you have received no clear cut impression of what the Negro in America is like, then you are in the same place with me. There is no The Negro here. Our lives are so diversified, internal attitudes so varied, appearances and capabilities so different, that there is no possible classification so catholic that it will cover us all, except My people! My people!”
—Zora Neale Hurston (1891–1960)
“The last publicized center of American writing was Manhattan. Its writers became known as the New York Intellectuals. With important connections to publishing, and universities, with access to the major book reviews, they were able to pose as the vanguard of American culture when they were so obsessed with the two Joes—McCarthy and Stalin—that they were to produce only two artists, Saul Bellow and Philip Roth, who left town.”
—Ishmael Reed (b. 1938)
“Time in the hand is not control of time,
Nor shattered fragments of an instrument
A proof against the wind; the wind will rise,
We can only close the shutters.”
—Adrienne Rich (b. 1929)
“Behold the Atom—I preferred—
To all the lists of Clay!”
—Emily Dickinson (1830–1886)