Quote from: ArcCsch on January 23, 2017, 03:13:54 AM

Quote from: bitsec731 on January 23, 2017, 02:03:41 AM

I am sorry but that just makes no sense, the information entropy of a number is raw entropy with 0% noise/signal ratio.

I am sorry but that just makes no sense.

Quote from: bitsec731 on January 23, 2017, 02:03:41 AM

When you consider a picture, which has bits of repeating colors all over the place, that is just not raw entropy anymore, because the bits of the colors are repeating. I highly doubt that is high quality randomness.
...
But just the dice itself, which is not even in the same language, I doubt it. It's the bits that are the language, and repeating bits are not a good quality.

The photo as is is not high quality randomness, but it has much more total entropy than the dice roll values.
Think about it, if you roll ten dice and record the values, they have 60466176 possibilities, how many possible images of the dice do you think there are?
Definitely many more, and entropy is just a measure of the amount of possibilities (adjusted by probability, so that equal probabilities have more entropy than different probabilities).
Also, high quality randomness is not very important for the seed value, a ten bit seed is inadequate no matter how high-quality they are are, but 65536 bits are enough even if each bit is biased 10% to 90%.

Alright I have to concede, cryptography is not my field, I'm an IT guy.

However I imagined that the seed is good if it's truly random. For example an image is a highly repetitive cluster of bits. When you have a blue dice on a white background, that is pretty easy to reconstruct and find similarities.

Random in the entropy sense means something that doesn't repeat, otherwise what is the point on generating a key from that.

If you have a picture of something where the bits are highly repetitive, doesn't that automatically mean low quality randomness?

It would be the equivalent of flipping coins where 1 side has an enormously bias. If you think of a picture as a bitmap, if the background is white,then that is already a huge bias. Then you have some blue, and the signs on the dice are also white. I doubt that is a high source of entropy.

So maybe a photography could be a source of entropy, but it should be a more diverse photo, like taking random photos of a town, and mixing it together as a composite, so that the colors and the patterns are more uniformly distributed.

I have also read that using a microphone to gather background nosie from an empty room is also a decent source.

It all depends on the quality too, I believe.