I must downsize and sell many significant books and papers in computer history. Topics include pioneering vacuum tube computers, early programming and user interface design, pioneering networking, and computer architecture ... Read More

Design principles help students learn the essentials of technical design tasks. Students apply simple-sounding rules to achieve desired design features. The trick is to present students with design principles they can see in real life, understand, and apply in their own efforts. Here are my observations on how to write ... Read More

This is a short, gentle two-part introduction to basic cryptographic concepts using text-based crypto examples. The videos illustrate encryption, decryption, ciphers, keys, algorithms, code cracking, cryptanalysis, and letter frequency analysis.  Full disclosure: I produced these videos over a decade ago. Now they are hosted directly on this web site. The ... Read More

I found this in my files. I no doubt intended to publish it months ago and forgot to finish it and press the button. Senior government officials traditionally restrict defense-related conversations to special locations to prevent eavesdropping. The most secret conversations occur in places like the White House Situation Room ... Read More

A person called me on the phone a few moments ago claiming to be from US Bank. He said there was some fraud detected on my account: someone created a new checking account with my identity information. “So, you have my identity information?” I asked. “Yes,” he replied. “Can you ... Read More

Quantum codebreaking uses a theoretically “large” quantum computer to break secret codes. Today, quantum computers handle very tiny numbers. The most impressive examples deal with numbers less than 22. In theory, a “large” quantum computer could quickly crack codes we use every day to protect data.  I’ve been skeptical about ... Read More

Journalists aren’t usually invited to online chats about US war plans. This seemed obvious until yesterday, when Atlantic editor Jeffrey Goldberg published his article about being a lurker in an online chat with US Secretaries of State, Defense, and Treasury, plus the VP and the Director of National Intelligence. The ... Read More

Do not call that number! This attack is brilliant. It uses a legitimate PayPal email message about a bogus payment to trick you into phoning a bogus PayPal phone number. I have received several of them this week with various names for the company sending the money request. Different emails ... Read More

Here is a set of geographical maps of the ARPANET in the 1970s and 1980s. There is also one “logical” map that focuses more on which host computers were connected where. The ARPANET was a precursor (some would say “the precursor”) to today’s Internet. It pioneered transcontinental and transoceanic digital ... Read More

It was only a matter of time before someone did this. Bitlocker is Microsoft’s technique for encrypting a desktop, laptop, or other MS Windows device. We encrypt the device to protect the contents if it is ever stolen. In theory, the only way Windows will start up if it is ... Read More