How the Internet Works

Part One

("How the internet works" talk starts at 8:30)

During this 49-minute episode, Leo and I briefly discuss the 'Kama Sutra' virus that will become destructive on February 3rd. We briefly discuss PC World Magazine's recent evaluation and ranking of ten top anti-malware systems. And we begin our long-planned 'fundamental technology' series with a two-part close look at the history and detailed operation of the global Internet.

Part Two

Leo and I discuss questions asked by listeners of our previous episodes. We tie up loose ends, explore a wide range of topics that are too small to fill their own episode, clarify any confusion from previous installments, and present real world "application notes" for any of the security technologies we have previously discussed.

How Local Area Networks Work

Having covered the operation of the Internet's WAN (Wide Area Network) technology in the past two weeks, this week Leo and I turn to discussing the way Local Area Networks (LANs) operate and how they interface with the Internet WAN. We address the configuration of subnet masks, default gateways, and DHCP to explain how packets are routed among machines and gateways within a LAN.


Modes of Encryption

("Encryption" talk starts at 2:20)

In preparation for a deep and detailed discussion of the Secure Sockets Layer (SSL) protocol, Steve and Leo first establish some formal crypto theory and practice of encryption operating modes.

Cryptographic HMACs

Leo and I discuss the role, importance and operation of cryptographically-keyed message digest algorithms and their use to securely authenticate messages: Hashed Messages Authentication Codes.

The SSL/TLS Protocol

Leo and I plow into the detailed operation of the Internet's most-used security protocol, originally called "SSL" and now evolved into "TLS." The security of this crucial protocol protects all of our online logins, financial transactions, and pretty much everything else.


Let's Design a Computer

Part One

To understand the advances made during 50 years of computer evolution, we need to understand computers 50 years ago. In this first installment of a new Security Now series, we design a 50 year old computer. In future weeks, we will trace the factors that shaped their design during the four decades that followed.

Machine Language

After starting at the very beginning two weeks ago by looking at how resistors and transistors can be used to assemble logical functions, this week Steve and Leo use those functions to build a working digital computer that understands a simple but entirely useful and workable machine language.

Indirection: The Power of Pointers

A feature present in the earliest commercial computers, known as “indirection”, has proven to be necessary, powerful, beneficial . . . and amazingly dangerous and difficult for programmers to “get right”. This week, Leo and I examine the Power of Pointers and why, even after all these years, they continue to bedevil programmers of all ages.

Stacks, Registers & Recursion

Steve and Leo continue their description of the operation of computers at the raw hardware level. This week Steve explains why and how computers have multiple accumulators, and also how a computer's "stack" operates and why stacks have become a crucial component of all modern computers.

Hardware Interrupts

In this fourth installment of Steve's “How Computers Work” series, Steve explains the operation of “hardware interrupts” which, by instantly interrupting the normal flow of instructions, allow computers to attend to the needs of the hardware that interacts with the outside world while they are in the middle of doing other things.


Going Random

Part One

This first week we open the topic and explain the background, problem and need. Week after next we'll plow into the solutions.

Part Two

We conclude our two-part series discussing the need for, and applications of, random and pseudo-random numbers. We discuss the ways in which a computer, which cannot produce random numbers, can be programmed to do an extremely good job.


How the Internet Works

Part One

("How the internet works" talk starts at 49:30)

Leo and I plow into the first of a series of forthcoming episodes, which will be spread out over time, describing the detailed technical operation of the ever-more-ubiquitous global Internet.

ICMP & UDP

Tom & I return for the second installment of "How The Internet Works" with a look at the ICMP and UDP protocols.


TCP

Getting Connected

("TCP" talk starts at 1:02:30)

Steve and Leo continue their "How the Internet Works" series with the first of several episodes describing the operation of the Internet's most used protocol: TCP.

Attacking TCP

("TCP" talk starts at 41:42)

Leo and I return this week to our “How the Internet Works” fundamentals series. We examine the operation of the various attacks that have been made through the years against the Internet's most popular and complex protocol: TCP.

Necessary Refinements

Leo and I return this week to our "How the Internet Works" fundamentals series. We examine the challenges presented by “packet-based connections” to further understand the operation of the Internet's most popular and complex protocol: TCP.


HTTP & SPDY

("HTTP & SPDY" talk starts at 29:00)

Steve and Leo take a detailed look at the World Wide Web's current TCP & HTTP protocols, and examine the significant work that's been done by the Chromium Project on “SPDY”, a next-generation web protocol for dramatically decreasing page load times and latency and improving performance and interactivity.


Interesting & Useful Intel History

Leo and I wind up and release our propeller beanies for a deep dive into the early history of Intel processor memory management - which, it turns out, has direct application to Steve's current work on SpinRite v6.1.