Archive for the 'Security/Cryptography' Category

Much Faster CryptoJS SHA1

May 17th, 2014
Spencer Nielsen Follow snielsen42 on Twitter

400px-SHA-1

SHA1 is a pretty crucial part of my current startup, Ultralink. We need to be able to have (relatively) decent uniqueness calculation and change detection and need to be able to do it really quickly on a lot of content. We picked SHA1 because it is widely supported, simple to implement and fast. For the portions of Ultralink that run in Javascript, we needed to include CryptoJS, a third-party library. CryptoJS appears to be the go-to library for cryptographic functions in Javascript and seemed to fit our bill perfectly. Development was humming along and everything was fine. We would occasionally do performance passes and stress tests on desktop web browsers and the SHA1 calculation wasn’t even on the radar for perf offenders. Once we started taking a look on iOS devices though, specifically Mobile Safari, then it was a completely different story… (more…)

Present.app

December 30th, 2012
Spencer Nielsen Follow snielsen42 on Twitter

Both my own siblings and my wife’s siblings have had a Christmas present exchange for the past couple of years and although the gifts are never extravagant, we always try to make them thoughtful. This year we thought it might be fun to give our siblings a choice of which present they wanted. We thought of making a card with the various options printed on it but then I came up with the idea of making a custom app that could serve the same purpose.

But I didn’t want it to simply be a card analog. It would have to take advantage of some of the unique features of iOS and do things that a normal card could not. Maybe we could somehow sneak it on to their iPads without them even knowing and surprise them with it! I was really excited about the idea and so I immediately sat down and started cranking it out. Thus, Present.app was born. (more…)

iOS 6 Predictions

March 6th, 2012
Spencer Nielsen Follow snielsen42 on Twitter

It is always fun to try and guess what Apple is going to do next. You can guarantee that there will always be surprises and sure bets, letdowns and magical moments. The Apple rumor sites do a decent job of soliciting leaks, reading between the lines and making educated conjecture. As a developer, I often like to take a good look at where Apple’s technology is right now and make logical extrapolations as to where things are headed. Oftentimes, when Apple announces some new feature or technology it seems obvious in retrospect if we had only connected the dots. Based on 2011’s release schedule, it is a fair bet to say that Apple is going to announce iOS 6 at WWDC sometime this summer and distribute a developer beta. That means that in the coming months little trickles of information are going to get doled out to the rumor sites about what kind of changes and additions we can expect. Just for fun, I wanted to get my own predictions out in the open before any of that started. Here is my very developer-oriented prediction list of what we might be expecting in iOS 6.


UPDATE: WWDC and the iOS 6 beta have come and gone. Some of my predictions now have conclusions. You will notice however that most of the predictions have not yet been updated. That is because there is the potential for Apple to be keeping a few more surprises up their sleeve for the fall when iOS 6 goes GM. Inline below are the results so far.


UPDATE2: iOS 6 GM is here which means that the NDA has lifted! Check down below to see how well I did. (more…)

Language Aid: A Postmortem

August 27th, 2011
Spencer Nielsen Follow snielsen42 on Twitter

Language Aid is a system-wide text lookup tool I developed and sold for the past couple of years. I recently decided to make it free and release the source code. This is the story behind it.

Rewind to 2006, I was just winding down active development of Vision, my OpenGL Window Sever/UI Framework. I had started work on Vision in college 3 years earlier and had been churning on it full-time for the previous 2 years. I had decided that it was finally time to get a job and so I interviewed around and accepted a position at Apple. I had two weeks until my start date and I wanted to do some programming for fun that was completely different from what I had been doing.

Iron Coder[0]

It was during that two week period of not yet working for Apple that Wolf Rentzsch started the (now defunct) Iron Coder contest. The way it worked was that the organizer announces an API that each of the contestants must use somehow in their entry and then 24 hours later a theme is announced that entries must also somehow incorporate. I thought it was just what I needed. A fun, small-scoped project with a little bit of competition. So the day of the very first Iron Coder arrived and the contest API was announced: The Accessibility API. Accessibility API? What’s that? Until that moment I had not been aware of it but it was actually just what I had been looking for to solve a different problem I had. I started researching it and immediately there were portions of it that were very interesting to me. Specifically, the ability for programs to inspect and copy data (like displayed text) out of other running applications was of particular interest to me.

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Language Aid 1.2

August 27th, 2011
Spencer Nielsen Follow snielsen42 on Twitter

Language Aid version 1.2 is out! The big feature of this release is that it is free and open source! This will also be the last release supported by Aoren Software. Development has pretty much wound all the way down at this point and the source has experienced some code rot as Core Foundation has progressively become more and more obsolete and Mac OS X has marched forward.

So it occurred to me that the time has come to set Language Aid free. Anyone care to take the code and modernize it? Maybe even release it on the Mac App Store? Let me know and I can work with you to make that happen. Be sure to check out my tell all Language Aid postmortem.

Exploring Airplay Mirroring Internals

August 20th, 2011
Spencer Nielsen Follow snielsen42 on Twitter

AirPlay Mirroring was without a doubt one of the coolest iOS 5 features announced to the public at the 2011 WWDC Keynote. This amazing technology allows you to display the screen of your iOS device on an Apple TV 2. At the moment, the only supported mirroring device is the iPad 2 and the receiving device is limited to only the Apple TV 2. Airplay Mirroring is the latest in a pedigree of Apple media streaming technologies. The previous entry in the family was Airplay Video and is a slightly different technology that allows specific content to be broadcast from a variety of iOS devices and iTunes to an Apple TV 2. The precursor to that technology was originally called AirTunes and is used to broadcast audio content from iOS devices and iTunes to the AirPort Express and Apple TV (either 1 or 2). One peculiar thing that people noted about AirPlay Video was that it was wide open and unencrypted! This was surprising in light of the fact that AirTunes was most definitely not. Because of AirPlay Video’s relatively easy hackability, there quickly sprang up all manner of apps for both Mac OS X and iOS which would act as an AirPlay Video consumer.

So my thought process went like thus:

  • AirTunes – Encrypted
  • AirPlay Video – Unencrypted
  • AirPlay Mirroring – ???

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Play MAME On Your iPad/iPhone Without Jailbreaking

July 25th, 2011
Spencer Nielsen Follow snielsen42 on Twitter

 

 

As a partial follow up to my previous article “Play SNES Games On Your iPad Without Jailbreaking” I have now made a similar patch to the imame4all project which will allow it to build for non-jailbroken iOS devices. Everything appears to be in order except that I havn’t figured out a way to get the BTDaemon to run on a non-jailbroken device. This means that it can’t currently use Bluetooth controllers like the Wiimote. Digging into the btstack source it looks like you can configure it to talk with a BTDaemon process even if it is running on another machine like a Mac. I havn’t had time to fully investigate that yet though.

How To Get It Working Yourself

I have created a patch and script that will create everything for you automatically and set you up so that you can just build, run and go. Like the SNES-HD- patch before, you are going to need a current copy of Apple’s Developer Tools (tested with Xcode 3.2.6) and a copy of the iOS SDK (my changes assume the 4.3 SDK). You will need to be a paid iOS developer with Apple and have correctly configured your development machine and iOS device so that you can sign code and run said code on your device.

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iPod Touch Server

June 11th, 2011
Spencer Nielsen Follow snielsen42 on Twitter


Top-down view of the Aoren Software datacenter in the living room corner.

Why, you might ask? In my case the answer is simply because it is my only alternative. In development of my game Cannonade there quickly arose a need to be able to replay my user’s completed games and validate the results with exactness. In order to obtain that level of exactness, my games must execute with complete determinism. Unfortunately the implementation of floating-point match according to IEEE754 can actually vary somewhat between x86 and ARM processors. This means that if I replayed a game that two of my users played using iOS devices on an x86-based server, the results of the replay would very quickly diverge. Thus I am left with no choice but to set up a dedicated iOS device to wait for notifications of the matches that it needs to replay and validate (a process I call judging). An iOS server you might say.

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Play SNES Games On Your iPad Without Jailbreaking

May 23rd, 2011
Spencer Nielsen Follow snielsen42 on Twitter

Apple gets a lot of flack over its curated app distribution model. No matter what your opinion on the subject is there is no doubt that for Apple’s model to have any sort of success it needs to be the only commercially realistic distribution avenue on the platform. This leads many people to jailbreak their devices for a variety of different reasons. Lets examine just the motivation of wanting to personally use non-App Store approved apps. The argument is then almost always framed as a dichotomy. I can jailbreak and get access to apps that Apple cannot or will not approve but risk damaging the device, violating warranty/support expectation, losing the ability to directly update to the latest OS version and introducing instability. Or I could keep my device in a stock configuration that will ensure stability and a clean upgrade path but miss out on some truly awesome and useful jailbroken apps out there. People don’t often remember that there is actually a third way to load apps onto your iOS device that has its own set of unique pros and cons. Apple fully supports loading apps on stock devices outside of the App Store through its developer program.

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Determinism in Games

January 28th, 2011
Spencer Nielsen Follow snielsen42 on Twitter

One day while I was hard at work a couple weeks ago I hit a really difficult technical snag. I stood up from my desk, let out a sigh and declared to the other person working in the office that “I’ve lost my determinism!”. He then inquired how I had lost my motivation while visibly wondering if I had used the word correctly. Although I had hit a significant roadblock, my determination to overcome it and make progress on my game was higher then ever. The “determinism” of my game however, had been lost. Now I needed to take it back.

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