a remote exam under exam conditions
April 28, 2011 8:01 PM Subscribe
How to record something digitally in a way that verifies it has not been 'shopped
posted by compound eye to computers & internet (21 answers total) 2 users marked this as a favorite
This is an experiment in remote education.
I want to film myself taking an exam as a way of verifying that the exam was done under exam conditions, without needing someone physically there to.. what's the word I'm after... invigilate the exam.
There are many problems to solve here and I am happy to hear your suggestions regarding any of the problems you imagine and possible solutions to them, but to maintain a bit of focus i want to concentrate on verifying the authenticity of the recording.
I have been imagining a version of the classic fitenss magazine before and after photos.
(where someone stands holding a copy of last months generic fitness magazine and their distended bare belly and then another photo the following month of them holding this months issue and their now rock hard abs after just one month of generic fitness magazine's one-month-rock-hard-abs-program)
So here's my current imagining:
The exam will be made available to me at a specific time*
The I will complete the exam so the work is done in view of the camera.
In the field of view of the recording there is a screen which is showing a random sequence of QR codes.
These QR codes are generated by a server which is recording the time each code was served.
Each frame of the video is then sent back to the server that makes a hash from the frame and the time using a secret key.
There will be a time lag between when the QR code was served, and when the frame containing the image of that code was hashed but it will be short.
If the video is edited, the correspondence between the frames, the times, and the QR codes will be broken.
So any trickery would have to be happening real time or it would be revealed.
In addition there will need to be a similar mechanism to verify the audio recording.
When I am finished the exam I will show all the work to the camera and place it in a provided envelope and close the security seals all in front of the camera.
The recording, the qr codes, the times and the hashes will be permanently stored on the server.
Does a system - or parts of a system - like this already exist?
If not, do you have any implementation suggestions?
Ok here's the extra peripheral stuff I don't want to be the focus of the question because otherwise the question just gets to big
I'm not sure how to deliver the exam, probably via the screen showing qr codes, where gestures in front of the camera provide a simple interface for navigating the text so that the I do not need to be provided with any kind of controller. Ideally I would do all the work on a whiteboard so the work is visible as it is done, but I don't know if this is a practical condition to impose on students.
Perhaps a convex mirror would need to be at the front of the room, but then what about the roof? What about messages sent by an accomplice using lasers shining on the floor? the list of potential exploits is long. Once the system is set up I'm going to try cheat it, and put the videos online and see if the public can accurately detect the cheats, and if not revise the set up.