Sunday 30 October 2016

A punched card reader in javascript

While trying out the Ektoparty CTF 2016 there was a challenge which requires to decode a series of punched card images. A punched card looks like this

A Punched Card
Fig 1: A sample punch card

The small white blocks denote the punch. All of the card images were specifically generated by an online service - Card punch. However, on searching for a tool which reads such images, I found nothing, hence I developed a small web app which can read in these punched card images. Please do note the card image must have an exact dimensions of 588 x 264 or else the tool wont work. You can try out the tool here or below. The source is on github.

2 comments:

  1. followed instruction to convert image to 588x264 loaded image but
    did not convert?

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    Replies
    1. At that time the images had a dimension of 588x264. It may have changed meanwhile. As a result even after resizing the image the punches won't be in the exact same position as was earlier.

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