This is live entropy from the Photonic Instrument. The three lines represent the red, green and blue pixel values (0-255) of a continuous strip across the middle of the webcam’s sensor. There are 500 data points on this graph, containing a true entropy of ~11 bits. That’s ~0.05% of the total entropy available from a single frame. This is based on a conservative entropy assessment of 1 bit/jpg byte along files approximately 20kB in size.

Note 1: This is simply the output of the JPEG algorithm, and is therefore only representative of the entropy generated by the Photonic Instrument’s webcam sensor. It’s really a product of discrete cosine transforms, quantization and Huffman decoding. You can think of these lines as pseudo-random entropy. The true entropy is the source JPG file itself.

Note 2: We endeavour to maintain this entropy source on-line at all times, but that’s not always possible. Sometimes maintenance is required, and it goes off-line when the instrument needs greasing. Most Bank holidays are out too. There will be a big red error box and an “An Error Has Occured…” message during the off times. Apologies.