Project: Decoding with OPTAR

A project for unix/linux by Derek Girardi during the fall 2011.

This project was begun on 10/27/11 and is anticipated to take 3 days.

The purpose is to decode a piece of paper with a secret message inside. I must find some way to decode the barcode like paper. I must find a way to decode it and manipulate it to find the message.

In order to successfully accomplish/perform this project, the listed resources/experiences need to be consulted/achieved:

• Manage files in unix/linux
• Run commands on the command line
• Archive handling
• Manipulate text through expressions
• Puzzle box

Optar stands for OPTical ARchiver. It's a codec for encoding data on paper or free software 2D barcode in other words. Optar fits 200kB on an A4 page, then you print it with a laser printer. If you want to read the recording, scan it with a scanner and feed into the decoder program. This can be used in many real life situations like in law, where you need to store data in a more compact way for accounting. or in media augmentation like putting data inside books, magazines and newspapers. It can also be used just for fun if you want to show it off for your friends. It does not have a man page but it can easily be downloaded and one can find help within its readme file. All you need to know for optical archiving is in there.

To apply skills learned in unraveling the puzzle that isn't as it may seem.

Make sure you look over everything carfully and have fun exploring :)

State and justify the attributes you'd like to receive upon successful approval and completion of this project.

• commands:demonstration/utilization of commands/tools
• files & directories: demonstration of paths/files/directories
• The UNIX shell:utilization of UNIX shell functionality
• The UNIX development environment:demonstration of development tools

There are many things that had to happen for this to happen:

• First we had to scan the image to read the data, We used scanimage –mode gray –resolution 600 –compression none > outfile
• We then wait for it to scan the image and we will see the pgm file appear to where the outfile was set. Most likely the directory you are currently in.
• You then you have to convert the pgm file to a png because thats what the program is able to translate. Use convert command
• Then you must run the unoptar program

./unoptar 0-67-87-24-3-1-2-24 WOONYAN > Gunther

• The numbers you see are the dimensions of the paper, they are only needed for this part and provided right on the paper for you. The program does it for you.
• Then once the program is finished, you should have 0% irreparable bits (its ok if its like .1 or so away) and you should have your file that contains the data on it.
• The paper i had had an audio file located on it, i will not say because its a secret and you need to figure it out on your own. :)

This project was a hard project but very fun. Its awesome seeing a audio file actually work straight from a piece of paper. I recommend for people to do this.

In performing this project, the following resources were referenced:

• http://ronja.twibright.com/optar/