WEBVTT 00:00:00.000 --> 00:00:04.520 Cloudflare handles over five trillion web page requests every day, 00:00:04.520 --> 00:00:09.520 most of which are encrypted to protect your data. But did you know that this encryption depends on 00:00:10.380 --> 00:00:14.120 lava lamps? I'm talking regular lava lamps, 00:00:14.120 --> 00:00:19.080 like you can get on Amazon, what? Does the lava have some kind of super secret 00:00:19.080 --> 00:00:22.520 processing capability that's soon to put AMD and Intel out of business? 00:00:22.520 --> 00:00:25.920 Obviously not, but the lava is a great source 00:00:25.920 --> 00:00:29.280 of natural entropy, which is a measure of disorder, 00:00:29.360 --> 00:00:33.440 if you think back to high school physics. The reason natural entropy is important 00:00:33.440 --> 00:00:38.240 is that it provides natural randomness, which can be used to encrypt data. 00:00:38.240 --> 00:00:42.400 You see, the lava inside a lava lamp, which is actually just wax, 00:00:42.400 --> 00:00:45.840 flows in naturally random unpredictable patterns 00:00:45.840 --> 00:00:49.840 once the lamp is heated, just like how you can't predict exactly how steam 00:00:49.840 --> 00:00:54.400 rises from a boiling pot, for example. A camera at Cloudflare's headquarters 00:00:54.400 --> 00:00:57.540 is pointed at a wall of approximately 100 lava lamps 00:00:57.580 --> 00:01:02.660 and takes a photo ever so often to capture the exact pattern the lava lamps are showing. 00:01:02.660 --> 00:01:06.900 Those photos are then sent to a computer that gives each pixel a numerical value 00:01:06.900 --> 00:01:11.300 depending on its appearance, creating a random numerical string 00:01:11.300 --> 00:01:14.500 that becomes what we call a cryptographic seed. 00:01:14.500 --> 00:01:17.700 This seed number is fed into a mathematical function 00:01:17.700 --> 00:01:22.700 that creates another seed, which then gets fed into a number generator whose outputs 00:01:22.700 --> 00:01:27.420 can be used for cryptographic keys, used to encrypt and decrypt traffic, 00:01:27.420 --> 00:01:31.300 making it difficult for attackers to see what you're looking at. 00:01:31.300 --> 00:01:35.180 These keys are also used to confirm that the communication actually came 00:01:35.180 --> 00:01:39.420 from the website you're connected to, preventing your data from flowing to an attacker 00:01:39.420 --> 00:01:42.520 that's pretending to be a legitimate service, 00:01:42.520 --> 00:01:47.860 but actually isn't a legitimate service. Besides lava lamps, some of Cloudflare's offices 00:01:47.860 --> 00:01:51.620 use swinging pendulums or rainbow mobiles 00:01:51.620 --> 00:01:56.060 that get blown around by the air conditioning. Even if someone were to walk in front of these installations 00:01:56.060 --> 00:01:59.260 and the camera captures their photo, that's actually completely fine, 00:01:59.260 --> 00:02:02.300 as that just adds a different kind of randomness to the image. 00:02:02.300 --> 00:02:07.700 Cloudflare even has an installation in Singapore where the natural decay of a chunk of uranium 00:02:07.700 --> 00:02:13.260 is the randomness source. But why all this rigmarole? It turns out computers are much worse 00:02:13.260 --> 00:02:16.260 than Mother Nature at generating true randomness. 00:02:16.260 --> 00:02:20.380 While there are lots of easily accessible random number generators out there, 00:02:20.380 --> 00:02:24.300 many of them are pseudo random rather than truly random. 00:02:24.300 --> 00:02:27.640 But what's the difference? Well, pseudo random number generators 00:02:27.640 --> 00:02:33.420 produce numbers by using an algorithm, meaning that they're predictable if you know the seed, 00:02:33.420 --> 00:02:37.300 as the same seed will produce the same output every time. 00:02:37.300 --> 00:02:42.220 Unless that seed is truly random, there's no actual true randomness in the process, 00:02:42.220 --> 00:02:46.060 meaning that you could guess a cryptographic key if you know the seed. 00:02:46.060 --> 00:02:51.740 And on many pseudo random number generators, that may not be that hard to do 00:02:51.740 --> 00:02:57.540 if the seed is something fairly easy to guess, like the date or the time as are commonly used. 00:02:57.540 --> 00:03:03.340 And this might be fine if you're just trying to decide on a random number for something like a D20 role 00:03:03.340 --> 00:03:06.500 in your D&D game. But for trying to keep internet traffic secure, 00:03:06.500 --> 00:03:11.100 a truly random hard to guess seed from a natural entropy source is essential. 00:03:11.100 --> 00:03:14.700 But if you're in need of a random number generator in your own home for whatever reason, 00:03:14.700 --> 00:03:18.740 we recommend lava lamps over radioactive materials 00:03:18.740 --> 00:03:22.020 in the long term, they're less bad for you. Thanks for watching guys. 00:03:22.020 --> 00:03:25.840 If you liked this video, check out our other video on a Cloudflare mishap 00:03:25.840 --> 00:03:29.020 that took a good chunk of internet offline. 00:03:29.020 --> 00:03:30.060 Those guys.