Posts filed under the 'PCPlus' category


PCPlus 315: Safe online transactions

In which I talk about how to solve the problem of communication between two entities (I talk about the archetypal Alice and Bob) so that no one else (notably, Eve) can listen in, and no one (especially Mallory) can monkey around pretending to be Alice to Bob or vice versa. (For those not in the know why these names were chosen, Alice and Bob just designate A and B, Eve is the eavesdropper and Mallory the man-in-the-middle.) I start off with DES (Data Encryption Standard), an old fashioned encryption...

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PCPlus 314: Choose the right password

This particular article sprung pretty much fully formed from an XKCD comic. It’s the one called “ Password Strength ” and talks about password entropy and about choosing a password by selecting four separate words at random. I’m sure my readers, sophisticated souls that they are, already know of it. I decided to flesh out Randall Munroe’s comic by explaining what information entropy is and how it applies to passwords. I talk about the entropy of an ATM PIN (which is generally just four digits) and...

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PCPlus 313: Evaluating a human

I can’t remember the genesis of this particular article on the Turing Test, but this year being the centenary of Alan Turing’s birth certainly makes it very apt a year later. In essence, in the early 50s Turing was considering the question: can machines ever be said to think? He was at the time involved in the building of the first general-purpose computer and, based on his work with the theoretical programmable machines now known as Turing machines, was pondering how intelligent these computers...

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PCPlus 312: Dynamic exposures

A photography topic this time: HDR photos. HDR stands for High Dynamic Range and is a set of algorithms that attempt to widen the range of detail in a photo from the darkest shadows to the brightest highlights to more closely mimic what the human eye can see. Here’s an example I created from our last trip to England: It’s a photo of Long Meg, the keystone of a large neolithic stone circle in the Pennines. Notice the artificiality of the lighting. The problem is that the screen you are using to view...

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PCPlus 311: Website security

Possibly a rather lightweight topic this one, but at the time (and frankly since) it was certainly in the news. The topic? Websites getting hacked, having customer data downloaded, including passwords. Sometimes the hacks are really simple, and I talk about a couple in the article: SQL Injection (which, even after all this time, is still one of the primary ways to hack a website) and XSS (cross-site scripting). Sometimes users bring the problems upon themselves by, say, having the same passwords...

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PCPlus 310: How your phone betrays your location

I’d have to say this article is perhaps the most satisfying of all the articles I’ve written for PC Plus. For a start, it did not even start out as an article but as some research I did to help my wife with a case (she’s a prosecutor). Some of the cases she prosecutes involve computers, and some involve some kind of techy knowledge she has to understand in order to present it to a jury. Seeing as I’m a kind of captive techy guy at home: I get asked questions about hashes, about deleted files, about...

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PCPlus 309: JavaScript uncovered

An article detailing the history of JavaScript, as well as a discussion about its major functionality. I’m going to guess I was late on this deadline, because I probably wrote it in my sleep, the topic was so familiar. Still it’s a pretty good overview of what JavaScript is and where it came from, so if you’re not sure what makes the guts of a “Rich Internet Application” (RIA) work, it’s a quick read. Almost sounds like the intro chapter to a possible JavaScript programming book… This article first...

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PCPlus 308: Understanding SSDs

A quick article about what SSDs (solid state drives) are and one that necessarily talks about NAND-flash, SLC (single-level cell) and MLC (multi-level cells), wear-leveling, TRIM, and all those other acronyms and jargon that crop up with them. I also detail the main difference between SSDs and USB thumb drives (the former will perform some kind of wear-leveling, the latter won’t). All in all, quite a fascinating article to research and to read. I will say that, having upgraded two of my laptops to...

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PCPlus 307: Spotting faked photos

At the time I wrote this article, there had been a couple of online articles about faked (or Photoshopped) photographs, especially ones used by reputable news organizations. I decided to take a look and do some research about how it was possible to detect faked photographs, especially those that are not really obviously done. The obvious fakes are, well, obvious, and funny, to boot . Pretty quickly I was led to the research of Professor Hany Farid , who seems to be the expert on image forensics....

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PCPlus 306: How 3D TV works

Without a doubt this article was an absolute hoot to write. I had the most fun researching the subject, buying an iPhone app, photographing my toy stuffed hedgehog, writing the article, reading press releases about Nintendo’s 3DS (it had only just been announced when I was writing this). In fact, doing everything except, you know, actually watching any 3D TV (we don’t have a telly, let alone a 3D one). In the article I quickly explain what a 3D effect is and how it works (each eye sees something...

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