Hal Abelson

Keys under doormats: mandating insecurity by requiring government access to all data and communications

Twenty years ago, law enforcement organizations lobbied to require data and communication services to engineer their products to guarantee law enforcement access to all data. After lengthy debate and vigorous predictions of enforcement channels “going dark,” these attempts to regulate security technologies on the emerging Internet were abandoned. In the intervening years, innovation on the Internet flourished, and law enforcement agencies found new and more effective means of accessing vastly larger quantities of data. Today, there are again calls for regulation to mandate the provision of exceptional access mechanisms. In this article, a group of computer scientists and security experts, many of whom participated in a 1997 study of these same topics, has convened to explore the likely effects of imposing extraordinary access mandates. We have found that the damage that could be caused by law enforcement exceptional access requirements would be even greater today than it would have been 20 years ago. In the wake of the growing economic and social cost of the fundamental insecurity of today’s Internet environment, any proposals that alter the security dynamics online should be approached with caution. Exceptional access would force Internet system developers to reverse “forward secrecy” design practices that seek to minimize the impact on user privacy when systems are breached. The complexity of today’s Internet environment, with millions of apps and globally connected services, means that new law enforcement requirements are likely to introduce unanticipated, hard to detect

Skill progression in MIT app inventor

This paper contributes to the growing body of research that attempts to measure online, informal learning. We analyze skill progression in MIT App Inventor, an informal online learning environment with over 5 million users and 15.9 million projects/apps created. Our objective is to understand how people learn computational thinking concepts while creating mobile applications with App Inventor. In particular, we are interested in the relationship between the progression of skill in using App Inventor functionality and in using computational thinking concepts as learners create more apps. We model skill progression along two dimensions: breadth and depth of capability. Given a sample of 10,571 random users who have each created at least 20 apps, we analyze the relationship between demonstrating domain-specific skills by using App Inventor functionality and generalizable skills by using computational thinking concepts. Our findings indicate that domain-specific and generalizable skills progress similarly; there is a common pattern of expanding breadth of capability by using new skills over the first 10 projects, then developing depth of capability by using previously introduced skills to build more sophisticated apps.

Measuring the usability and capability of App inventor to create mobile Applications

MIT App Inventor is a web service that enables users with little to no previous programming experience to create mobile applications using a visual blocks language. We analyze a sample of 5,228 random projects from the corpus of 9.7 million and group projects by functionality. We then use the number of unique blocks in projects as a metric to better understand the usability and realized capability of using App Inventor to implement specific functionalities. We introduce the notion of a usability score and our results indicate that introductory tutorials heavily influence the usability of App Inventor to implement particular functionalities. Our findings suggest that the sequential nature of App Inventors learning resources results in users realizing only a portion of App Inventors capabilities and propose improvements to these learning resources that are transferable to other programming environments and tools.

The first-course conundrum

Recently, the College Entrance Examination Board (CEEB) has decided to redesign the Advanced Placement (AP) examination in computer science (CS) so that AP courses will be forced to switch from Pascal to C++ starting around 1998.

Live Programming of Mobile Apps in App Inventor

MIT App Inventor is a programming environment that lowers the barriers to creating mobile apps for Android devices, especially for people with little or no programming experience. App Inventor apps for a mobile device are constructed by arranging components with a WYSIWYG editor in a computer web browser, where the development computer is connected to the device by WiFi or USB. The behavior of the components is specified using a blocks-based graphical programming language. A key feature in making App Inventor accessible to beginning programmers is live programming: developers interact directly with the state of the evolving program as it is being constructed, and changes made in the web browser are realized instantaneously in the running app on the device. This paper describes the live programming features of App Inventor and explains how they are implemented.

Teaching with app inventor for android (abstract only)

App Inventor for Android is a visual blocks language for building mobile apps. Like Scratch, the languages drag-and-drop blocks interface significantly lowers the barrier to entry. Beginners can immediately build apps that interface with mobile technology (e.g., GPS, Text-to-speech, SMS Texting) and build apps that have a real-world impact. App Inventor has great potential for increasing interest in programming and attracting women and other underrepresented groups to computer science. Students learn by tinkering with their most beloved devices, phones and tablets, and even novices can create apps in an exciting and intuitive environment. App Inventor is relevant to teachers from middle school through the university level who are interested in a highly motivating method of teaching programming. In this BoF, we will discuss the language, its future in K-12 and university education, and its new home at the MIT Center for Mobile Learning.