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ShowMeDo: WASTE tutorial

My ShowMeDo tutorial Secure File Transfer With WASTE has just gone online. ShowMeDo is web site for tech tutorials in flash video – the majority are screencasts on varied programming topics. ShowMeDo has huge potential for learning new technologies, I think its going to get bigger and bigger…

Flash video

Experimenting with flash video – and time-lapse. This involved a few free source apps:

  1. Time-lapse video: MakeAVI,
    virtualdub to dub the soundtrack (although I found out virtual dub can do the time-lapse stuff itself).

  2. Creating the flash video file: FFmpeg, there’s a tutorial on it here: FLV encoding with ffmpeg.
  3. Jeroen Wijering’s Flash Video Player

TWOCrowds.com flickr CAPTCHA test

Noticed on the web somewhere TWOCrowds.com is using the flickr api to create a CAPTCHA test. Looks like they are using the flickr api to pull up a photo tagged with a convention that says “this is a photo of a single letter: r”.

Wouldn’t this be pretty easy to defeat? The JPG’s are being served from flickr – and a named like this: “114556884_45d6dd4ec4_s.jpg”. The first part of the filename is the photo id which you can pass to the flick API method flickr.photos.getInfo. Which returns all the tags (among other things) for the image – the “Rr” tag being the convention that says this is a photo of the letter R:

    <tags>
        <tag id="256536-114556884-484" author="95229107@N00" raw="Paris">paris</tag>
        <tag id="256536-114556884-6562" author="95229107@N00" raw="claudecf">claudecf</tag>
        <tag id="256536-114556884-17897" author="95229107@N00" raw="letter">letter</tag>
        <tag id="256536-114556884-67834" author="95229107@N00" raw="oneletter">oneletter</tag>
        <tag id="256536-114556884-6496" author="95229107@N00" raw="letters">letters</tag>
        <tag id="256536-114556884-8513" author="95229107@N00" raw="Rr">rr</tag>
    </tags>

They could prevent this by not revealing the image names in the HTML – by having their webserver read in the JPG and delivering it with a different filename.