feat: Principle of Least Privilege

README.md

@@ -84,6 +84,7 @@
     - [YAGNI](#yagni)
     - [The Fallacies of Distributed Computing](#the-fallacies-of-distributed-computing)
     - [The Principle of Least Astonishment](#the-principle-of-least-astonishment)
+    - [The Principle of Least Privilege](#the-principle-of-least-privilege)
 - [Reading List](#reading-list)
 - [Online Resources](#online-resources)
 - [PDF eBook](#pdf-ebook)
@@ -833,7 +834,7 @@ The name of this principle comes from a story by [G.K. Chesterton](https://en.wi
 
 [Kerckhoffs's principle on Wikipedia](https://en.wikipedia.org/wiki/Kerckhoffs%27s_principle)
 
-> "...design your system assuming that your opponents know it in detail."
+> ...design your system assuming that your opponents know it in detail.
 >
 > _Steven M. Bellovin's formulation of Kerckhoff's Principle_
 
@@ -843,7 +844,16 @@ The gold standard for any secret-keeping system is that implementation details s
 
 The history of cryptography has shown that open discussion and analysis of cryptographic systems leads to better and more secure systems - as researchers are able to test for and expose potential vulnerabilities.
 
+This is the third of five noteworthy design principles from [Protection and the Control of Information Sharing in Multics](https://dl.acm.org/doi/10.1145/361011.361067) (Saltzer, 1974), where it is noted for its value in the design process:
+
+> This principle is not new ... but its violation sent a surprising number of design proposals back to the drawing boards.
+>
+> Jerome H. Saltzer
+
+See also:
+
 - [Shannon's Maxim](#todo)
+- [The Principle of Least Privilege](#the-principle-of-least-privilege)
 
 ### The Dead Sea Effect
 
@@ -1129,6 +1139,29 @@ See also:
 
 - [Convention Over Configuration](#todo)
 
+### The Principle of Least Privilege
+
+[The Principle of Least Privilege on Wikipedia](https://en.wikipedia.org/wiki/Principle_of_least_privilege)
+
+> Every program and every privileged user of the system should operate using the least amount of privilege necessary to complete the job.
+>
+> _Jerome H. Saltzer_
+
+Also known as the **principle of least authority**, this principle requires components to be designed so that they need a minimum of privilege, authority, access, or permissions to accomplish their design goals.
+
+A system designed with least privilege has a natural partitioning into isolated subsystems which do not interact with each other. By intentionally restricting privileges during the design phase, a system can be produced which enforces that partitioning during operation.
+
+This is the fourth of five noteworthy design principles from [Protection and the Control of Information Sharing in Multics](https://dl.acm.org/doi/10.1145/361011.361067) (Saltzer, 1974).
+
+See also:
+
+- [Kerckhoffs's principle](#kerckhoffss-principle)
+
+Real-world examples:
+
+- [Need-to-know policies](https://en.wikipedia.org/wiki/Need_to_know) in military organizations
+- [Capability-based security](https://en.wikipedia.org/wiki/Capability-based_security), where all privileges are idealized as unforgeable copyable references
+
 ## Reading List
 
 If you have found these concepts interesting, you may enjoy the following books.