Scankoffer

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What is it? questionmark

In the remote connection / VPN world, RSA tokens and other two-way authentication methods are used to increase security. At my work we have a box full of these tokens laying around. I had an old scanner laying around, and decided that it would be a good project to create someting that makes pictures of these RSA tokens for me.

I took a Raspberry PI and hooked it up to the camera module that was just released. The steppermotor of the scanner was reused and hooked up to a motor board from bitwizard.
With some code, a picture could be downloaded via FTP as soon as you got the filename from the protocol created for this project.

At my work we have created a Windows Forms application that is connected to our CMS and knows on what position a token is located in order to make a photo.

C++ code questionmark

The code can be found on my github https://github.com/timdows/raspberry-projects/tree/master/Scankoffer

The code is condensed into one file with 6 functions:

  1. int main
    Creates a socket and opens a TCP port. It will listen for new connections and forks a child process on every incoming connection.
  2. void processConnection
    Handles all communication once a connection has been established.
  3. string timestr
    Returns a string to make filename of.
  4. string execWithOutput
    Execute a system command and grab the output of its return.
  5. void writeToSockect
    Write data back to the socket.
  6. void error
    Prints the error and exits the process.

Next to this, there is a ping daemon running to check if the WiFi connection is up and running. As soon as the daemon has a couple of ping failures to a server on the local network, it will bring the WiFi down and up in order to restore the connection.

Output of a connected client

End result questionmark

Some test tokens
Test token
Cutting of part of an old HP scanner to fit it into a briefcase
Scanner base plate in the briefcase with the slider rails intact
Installing the Raspberry PI onto the rails
Experimenting with a reading glass to make macro pictures
Installing a relay to switch the CCFL on and off
The flex ribbon on the side provides the power to it all
Installing the stepper motor driver
Also a DC-DC step down converter has been installed
Making a test photo
Making a test photo
What a dusty screen…
The end result
The 6 relay board has been replaced by a two relay board
When the scanner is at the start position
To finish it all off, a plastic plate was installed and a laser cut wooden plate to make sure the tokens are always in the correct place
The briefcase is most of the time closed, and we hear the relay for the CCFL from time to time ^^

TODO questionmark

  1. Could be cool if the scanner could have been expanded with another axis in order to scan more tokens

Project costs in € or $ questionmark

Object Price
Raspberry Pi model B (512MB) € 21
Raspberry Pi Camera Board € 25
WiFi module € 19
Raspberry Pi Serial BoB € 4.95
Relay board € 12.45
Motor board € 24.95
Old scanner € 5
DC-DC step-down convertor € 4.95
Briefcase –
Glasses € 3
Cables and other materials € 15
Total € 135.30

What could be better questionmark

  1. As it was one of my first projects, it is really still a prototype used in a production environment.
    With the time and money, a real product could be made of this prototype.

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