E: An Object-Oriented Programming Language for Secure Distributed Computing
In the rapidly evolving world of distributed computing, ensuring security, scalability, and robustness of systems has become a critical priority. The design and development of programming languages tailored specifically to meet these demands are pivotal for creating secure and reliable applications. Among these, E stands out as a specialized object-oriented programming language designed with the primary goal of secure distributed computing. Created in 1997 by Mark S. Miller and Dan Bornstein at Electric Communities, E combines several innovative features that distinguish it from other languages, especially in the domain of distributed and concurrent systems.
This article explores the design, features, history, and significance of E, focusing on its contributions to secure distributed programming, its relationship with other languages, and its current status in the programming community.
Introduction to E Programming Language
E is an object-oriented programming language created to facilitate secure distributed computing. It was primarily designed to address the challenges of building secure and reliable distributed systems, particularly in environments where different components of the system may be running on separate machines or in different domains. E is not just an experimental language but a practical tool designed to address real-world security concerns in distributed computing.
Unlike traditional programming languages, which assume that the computing environment is either centralized or secure by default, E is built with the assumption that the environment is inherently untrusted. This means that security and privacy considerations are integral to every aspect of the language’s design.
The Origins and Evolution of E
The roots of E lie in the concurrent programming language Joule, which was itself a language designed for distributed systems. Joule introduced several key concepts such as message-passing between objects, which E later adopted and expanded upon. E was developed as an extension of Original-E, a set of Java-based extensions that introduced security features for distributed systems. However, E sets itself apart from its predecessors through its more refined security model and focus on preventing issues such as deadlock, which is a common pitfall in concurrent systems.
Mark S. Miller, one of the language’s creators, was heavily involved in creating secure software systems and was deeply motivated to develop a language that would address the inherent security flaws found in most distributed systems. The result was a language that integrates principles of object-oriented programming with a robust security model, ensuring that deadlocks and other concurrency issues could be avoided.
Key Features of E
1. Object-Oriented Design
E is fundamentally object-oriented, and as such, it supports the key principles of object-oriented programming (OOP), including encapsulation, inheritance, and polymorphism. However, what sets E apart from other OOP languages is its emphasis on secure communication between objects.
In E, objects interact by sending and receiving messages in a way that ensures that no unauthorized actions can occur. Every object in E is a potential boundary for security, and communication between objects is restricted and controlled, making it ideal for distributed systems where components may be running in untrusted environments.
2. Message-Based Computation
At its core, E is built around message-passing computation. This is a central feature borrowed from actor-based programming models, where independent entities (actors) communicate exclusively by sending messages. This model is ideal for distributed systems, where components might be running on separate machines, and synchronous or direct method calls are not feasible. The language’s focus on asynchronous message passing makes it inherently more suitable for concurrent programming environments, reducing the risks of synchronization problems.
3. Concurrency and Event Loops
One of the major advantages of using E for distributed computing is its event-loop concurrency model, which is built into the language itself. Event loops allow E to handle multiple tasks simultaneously without the traditional issues related to thread management or deadlock. The concurrency model is based on the use of promises, which are placeholders for values that are computed asynchronously. When an object sends a request, it receives a promise, which is eventually fulfilled when the computation is complete. This design ensures that deadlock can never occur, making it highly robust for building reliable distributed systems.
4. Security Model
The most significant feature of E is its security architecture. E was specifically designed to be resistant to common security vulnerabilities found in distributed systems. The language’s security model is based on capabilities, which are special tokens that allow an object to perform specific actions. Only objects that possess the correct capabilities can access certain resources or perform privileged actions. This ensures that objects cannot inadvertently or maliciously access data or functionality they are not authorized to use.
In this sense, E functions similarly to a capability-based security model, where capabilities are used to enforce access control at a very granular level. This approach provides a level of security that is much more robust than traditional access control mechanisms like permissions or role-based security.
5. Deadlock-Free Design
Deadlock is a major concern in any system that involves concurrency. Traditional concurrent systems, which rely on threads and locks, are prone to deadlock when two or more threads wait on each other to release resources. In E, however, the design is such that deadlock is virtually impossible. The event-loop model ensures that all processes can continue without any of them waiting indefinitely for others. This is a major advantage when developing distributed systems where resources may be spread across multiple machines.
E’s Relationship to Other Programming Languages
E is often compared to languages like Java and Python, primarily because of its object-oriented nature and its high-level abstraction. However, while it shares many syntactical similarities with Java, E diverges in its focus on secure distributed systems and message-passing concurrency. The language’s features are more closely aligned with languages designed for secure and robust network programming, such as Erlang or Go.
Another important comparison is with Joule, the language from which E is descended. While Joule was one of the first languages to introduce the concept of message-passing concurrency in a distributed setting, E has built on this idea and integrated additional features, particularly in terms of security and the prevention of deadlocks.
Additionally, E’s security model bears some resemblance to Java’s security model, especially in its use of sandboxing and capabilities. However, E takes these ideas much further, offering a more explicit and robust system for managing access control and communication in distributed systems.
Current Status of E
Though E was created in the late 1990s, its impact on the world of secure distributed computing remains significant. While not as widely adopted as some of its contemporaries, E has found a niche audience in areas where security and distributed programming are paramount.
The language has maintained an open-source status since its inception, making it accessible to developers interested in experimenting with its unique security features. E is also supported by a website, eRightS, which houses resources, documentation, and community discussions.
However, the number of central package repositories and the broader adoption in the developer community remains low, possibly due to the specialized nature of the language and its narrow focus. Despite this, its design principles have influenced modern programming languages and systems, particularly in the realms of secure messaging and distributed computing.
Future of E
E remains an experimental and somewhat niche language, but its underlying principles continue to influence secure distributed computing. As cloud computing and distributed systems grow in complexity and scale, the importance of secure communication between system components becomes even more critical. Languages like E, which prioritize security from the ground up, are likely to remain relevant as foundational building blocks for systems that need to be secure and reliable.
While E may not become a mainstream language in the broader programming community, its legacy as a language for secure distributed computing, particularly in terms of its capability-based security model and deadlock-free concurrency model, is undeniable. The language’s focus on security and concurrency is highly valuable for specialized applications in areas like blockchain development, secure messaging, and distributed system design.
Conclusion
E is a language that serves a unique and important role in the world of programming. Designed specifically for secure distributed computing, it integrates advanced features such as message-passing, event-loop concurrency, and capability-based security, making it a powerful tool for building secure, distributed systems. While its adoption may be limited, the language’s contributions to the fields of security and concurrency remain influential, particularly for those working in environments where trust and reliability are critical.
As distributed systems continue to evolve and the need for security grows, E’s specialized design will likely remain a valuable resource for those tasked with building secure and resilient computing environments.
References
- E Programming Language Wikipedia
- E Programming Language official website: http://erights.org/