[Noisebridge-discuss] File format specification

[Shannon Clark]

Not my exact area of expertise by far but wouldn't XML also give you  
fairly standard ways to handle Internationalization and multi-byte  
Unicode etc? Which I'd imagie you probably would want to do in an open  
standard. And I would guess there are any number of open libraries  
around XML handling?

Shannon

Sent from my iPhone

On Mar 18, 2010, at 5:21 PM, Jacob Appelbaum <jacob at appelbaum.net>  
wrote:

> Hi,
>
> I'm working on a new file format for magnetic stripe information. I'm
> calling it MagPack. There are many dirty hacks but I don't believe  
> there
> are any actual open standards. If someone knows otherwise, I'd be  
> happy
> to be corrected!
>
> Here is an introduction to some of the details and ideas:
> http://code.google.com/p/libmsr/source/browse/trunk/README.file-specification
>
> The next step is to define a structure for captured data and for
> relevant meta-data. I'm starting to ponder the actual format of the  
> data
> on disk. There are many options (please not xml!) but it's unclear on
> what is the most cross platform, least external library dependent,  
> easy
> to use, easy to protect, easy to compress, etc.
>
> There are a variable number of elements for a given captured signal.
> Assuming that a user has a simple ISO formatted magnetic stripe, it's
> quite simple to store it as a byte array. It is important to include
> meta-data about the capture (date, time, reader, host OS platform,  
> etc)
> in any MagPack file. It's also important to allow repacking, re- 
> encoding
> and other stuff. I'd like to be able to encrypt a MagPack file, so the
> contents should probably be properly encapsulated...
>
> The data captured is entirely arbitrary. It may contain any byte
> sequence. It will certainly contain binary information (from raw bit
> patterned reads), it will possibly have blobs of images (png, bmp,  
> etc),
> it will hopefully have UTF-8 strings for any field related to the
> meta-data...
>
> What's a reasonable way to accomplish this? Should I just stick with  
> the
> simple "bunch of files in a folder, tar, gzip, possibly encrypt"  
> method?
> Should I get fancy and use XML, possibly encrypting the .xml file with
> an unencrypted header?
>
> In an ideal world, I'd like to do it entirely in pure C and in a
> portable manner. This tends to push me away from XML and then there's
> XML that pushes me away from XML. But is a custom binary format  
> better?
> Isn't that why XML was invented? To solve just this problem?
>
> Best,
> Jake
>
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