QR codes for evidence tracking

QR codes seem to be popping up everywhere now, from adverts & marketing campaigns to tracking and tickets. It’s easy to see why; they are easy to generate, have a high level of error-correction and the ability to encode quite a lot of data (the maximum being 4,296 alpha-numeric characters). Since most modern smart phones have the ability to decode them they present a much simpler way for people to get their information across – for example its much quicker and easier to scan a code on a house’s for-sale sign which links directly to the exact URL for that property, than to print the URL on the sign (for one it probably won’t fit, and secondly it’ll be the estate agents homepage and not the specific URL).

It therefore makes sense to use QR codes in forensics for evidence tracking. Some companies may choose to use barcodes, but this requires barcode scanners and generators which can be expensive. There are many QR code generators for free, and as mentioned above any modern smart phone can read them, so no fancy equipment is required. First you need to decide what data exactly to encode. An example would be the following:

  • Company / police force
  • Case name or reference
  • Exhibit reference
  • Exhibit type
  • Date first brought into custody 

An example using this format would be: Sarah Forensics Ltd | Project SecretSquirrel | Exhibit SCH-HDD001-SG004FAA1 | Seagate Harddrive 500GB | 09-APR-2014. Using Python you can generate a QR code by using the QRcode package and writing the following:

import Image
from qrcode import *

qr = QRCode(error_correction=ERROR_CORRECT_L)
qr.add_data("Sarah Forensics Ltd | Project SecretSquirrel | Exhibit SCH-HDD001-SG004FAA1 | Seagate Harddrive 500GB | 09-APR-2014")
img = qr.make_image()

qr_image_location = 'qr_code.png'
img.save(qr_image_location, "PNG")

Which generates the following image:


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