this post was submitted on 06 Nov 2023
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[–] Turun@feddit.de 10 points 1 year ago* (last edited 1 year ago) (1 children)

Every random number is actual pseudo random

No, there are true random sources in a computer. Any outside input can be used to generate randomness. Mostly user input, but temperature fluctuations can work as well, if the sensor precision is high enough.

Also the argument is only correct on a technical level for PRNGs. Choose a 65535 sided dice and make the instructions a thousand steps long and you'll have a pretty hard time to deduce the instructions from the generated numbers. Not to mention how long the list of numbers needs to be for the attacker to start guessing.

[–] Honytawk@lemmy.zip 1 points 1 year ago (2 children)

It is all based upon calculations with known numbers.

A computer can't create a number out of nothing.

That is why Cloudflare uses lava lamps to generate random numbers for their cryptography. And even those aren't fully random.

[–] vrighter@discuss.tchncs.de 7 points 1 year ago

Modern cpus actually do have trng hardware built in. So yes, modern computers can create numbers out of nothing, because they have specialized hardware to do so

[–] FooBarrington@lemmy.world 3 points 1 year ago (1 children)

No, CloudFlare doesn't use lava lamps to generate random numbers, that was a marketing stunt. Using a camera in a completely dark room is a better source of entropy than one pointed at lava lamps.

Also, nobody is saying that computers create a number out of nothing. The environment is a great source of entropy (temperature fluctuations, user inputs and so on) which are then expanded into a larger amount of entropy through CSPRNGs.

[–] Karyoplasma@discuss.tchncs.de 1 points 1 year ago (1 children)

Using a camera in a completely dark room is a better source of entropy than one pointed at lava lamps.

Why is that? Naturally occurring or manufacturing-related impurities in the optical chip?

[–] FooBarrington@lemmy.world 1 points 1 year ago

All digital cameras are imperfect - there is always a bit of noise, but usually it doesn't come through since your scene is bright enough to make small amounts of noise imperceptible. In a completely dark room the camera still tries to get data from the photo sensor, but the noise (created by temperature fluctuations, imperfections in the chip itself and so on) is all you get. You may theoretically be able to predict the noise on short time scales, but it's a chaotic system.