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On SSL/TLS and HTTPS — Briefings for my Computer Security class

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Brief: This is a technical briefing I made for fellow students in a Computer Security class (Winter 2011) about Secure Socket Layer [SSL] (now Transport Layer Security [TLS]). These briefings fit in nicely since it came after Dr. Obimbo explained the number theory behind RSA (modulus prime exponentiation). I went to the primary source on this topic to write this document: thanks to the Internet Engineering Task Force. I’ve posted this document as a consumable reference for anyone who needs it.

>>> Download: A Network Security Spotlight on SSL/TLS and HTTPS (pdf) <<<

Figure $_: A Schematic of the SSL/TLS Handshaking Procedure.

This document is licensed under Creative Commons Attribution 3.0 Unported. The enclosed figures are further released into the public domain.

Eddie Ma

February 16th, 2012 at 1:29 pm

Phew! Sun Virtualbox Port Forwarding (on NAT) Solution

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I finally found a solution for the port forwarding issue I was having with Sun VirtualBox (i.e. NAT provided a weird one-way mapping from which Tin (host) couldn’t dial into TinUbuntu (guest)…) — as far as I understand, this solution is guest operating system neutral but must be configured for each guest handled by a particular installation of Sun VirtualBox. That means that if you’re crazy like me and plan to put your virtual harddrives on USB sticks, you’d probably do just as well to put in a makefile that will do your configurations for you too. So here’s the solution, also saved in my wiki for extra truthiness!

Thanks to Evan and his “justwerks software” blog.

The following commands were issued…

cd /Applications/VirtualBox.app/Contents/MacOS

$VBoxManage setextradata "TinUbuntu"\
     "VBoxInternal/Devices/pcnet/0/LUN#0/Config/guesthttp/Protocol" TCP

$VBoxManage setextradata "TinUbuntu"\
     "VBoxInternal/Devices/pcnet/0/LUN#0/Config/guesthttp/GuestPort" 22

$VBoxManage setextradata "TinUbuntu"\
     "VBoxInternal/Devices/pcnet/0/LUN#0/Config/guesthttp/HostPort" 2222

Which causes TinUbuntu TCP:22 to be forwarded to Tin TCP:2222.

In future, I should remove these rules and re-add them replacing “guesthttp” with my own name for this rule– In his blog, Evan has used a series of names: “guesthttp”, “guestssh” and “guestsql”– In reality, these are actually very good, unambiguous names that I’ll probably end up borrowing.

The one thing I should really dig around for is the meaning of “LUN#0”– it looks like something that’s important– the remaining virtual-directory-like objects in the configuration string look less daunting– “pcnet/0” is likely referring to the first virtual network adaptor connected to TinUbuntu.

Eddie Ma

October 16th, 2009 at 10:05 am

Posted in Technology

Tagged with ,

Zinc, the Entertainment Unit

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Firefox Eats Cara's TV

Firefox Eats Cara's TV

Way back at the beginning of this month, I sent away to Apple to order a DVI-I to S-Video / RCA connector. The total cost was $35 after shipping and tax, so it was well worth it as now I’ve gotten yet more value out of the Mac Mini.

The circa 1980’s television set can now play all of the media that is on the network, on the internet or on whatever other storage you can plug into Zinc, the Mac Mini.

 

DVI-I to S-Video and RFA

DVI-I to S-Video and RCA

Technical Stuff about DVI Connectors

When looking for a DVI to RCA video connector, the wrong thing to do is to go to a big computer shop. These places will turn you away and tell you the part doesn’t exist. Heck, even the hobby shops failed to provide it or give any useful information. And you know– they’re half right. There’s no such thing as a DVI-D to RCA connector, because the former is a digital signal, and the latter is an analogue signal. The DVI-I is port is offers a combined digital and analogue signal, that’s how it can be converted out to such a large variety of display devices. It’s one of the selling points that Apple discusses about its laptops and other machines.

Buy it or not…

If you purchased a computer with a DVI-D output, you won’t be able to use Apple’s connector– so don’t try, you’ll waste your money and be frustrated– however, if you have a machine with DVI-I output, then this thing will work for you too even though big and small shops alike will tell you the connector doesn’t exist.

AirBag

Simply Charming

I also got two charming flotation device / pillow / toys packaged with the connector!

Conclusion: I’m happy 😀

Eddie Ma

July 12th, 2009 at 4:25 pm

Monet Molecules c/o Autotrace

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A Monet Isopentenol c/o Autotrace

A Monet Isopentenol c/o Autotrace

Brief: Happy accidents make me happy– here’s isopentenol after grabbing it as an SDF out of PubChem, dumping it out into a PNG with Bioclipse, grayscaling it with GIMP— then converting it to an SVG with Autotrace (RO IT Systems)… It’s just pretty… like a Monet. Of course, I have to go back and make it look like a molecule again for a paper… but I’m going to admire the pretty little alcohol for a bit.

Eddie Ma

July 9th, 2009 at 2:56 pm

Posted in Featured,Technology