5 ms·

Now that's a perfect example of something that seems obvious in hindsight, but obviously wasn't since the problem has existed for so long without a solution. I

• rwg 15y ago
  VIA's "Nehemiah" core C3 CPUs had hardware random number generation, as well as hardware AES assist, way back in 2003. (And, of course, VIA's "PadLock" instructions and Intel's RdRand instruction + AES-NI instructions are totally different. Hooray for continued x86 instruction set fragmentation!) Edit: It just occurred to me that you're probably referring to the implementation, not the existence of a hardware RNG in x86. Doh!
  • wmf 15y ago
    Yeah, IIRC VIA is using the same ring oscillator style that Intel used to use. This article is about a new, lower-power RNG design.
    • marshray 15y ago
      The idea that a hardware RNG would ever need to consume a noticeable amount of power on a 20W CPU seems strange to me. Lots of low power chips have them. A quick search returns a paper titled "A 2.92μW Hardware Random Number Generator".
      • jbri 15y ago
        Having a look at that paper, the actual rate at which it produces bits is very low - for 2.92μW, they're producing only 500 bits per second. For an embedded device that might be suitable, but for a consumer or server machine you need a much higher bitrate.
        • tedunangst 15y ago
          You only need a little "grade-A" random to seed an appropriate high bitrate algorithm from time to time.
        • marshray 15y ago
          No one has ever broken a properly designed CSPRNG properly seeded with more than 100 or 200 bits of entropy, total.
• marshray 15y ago
  No. There has been no shortage of perfectly workable designs for hardware random number generators patented over the years. If anything, it's something that engineering types with a fondness for crypto obsess about too much. The reality is that it's just not that hard to generate quality random numbers after a few seconds have passed after bootup on a busy system. Nothing needs gigabit rates of random numbers. The cases where applications have had lousy random numbers have all been boneheaded implementation bugs (like the early 90s Netscape one the reference). There are two reasons why this had not been implemented until now: 1. Low demand. It's entirely practical for applications to generate random numbers in software, especially with help from the kernel. With a hardware RNG on some chips, a fallback implementation would still have to be available and people who care about their CSPRNGs in software wouldn't fully trust Intel's numbers anyway. 2. Additional design, documentation, and testing burden. Every feature has a cost. The cryptographic qualities of random numbers are nearly impossible to test as a black box.
  • palish 15y ago
    Speaking as a graphics programmer, I hope to see this hardware-level randomness eventually incorporated into GPUs. Randomness on a GPU is hard, and there are so many ways that a RNG can improve visual quality. For example, adding a tiny amount of film grain to the final rendered image would most easily be done with RNG. Another example: it's common for renderers to accumulate the scene's illumination into a HDR texture, and then radially blur it. The goal is to approximate the halo you observe around light sources at night time. The problem is, a Gaussian blur is perfectly smooth --- so the resulting glow typically ends up being a perfectly smooth blurry circle of light. But a real photograph of the same scene rarely has smooth glows. The image exhibits all kinds of subtle noise in the light's corona. After all, a photograph results from interaction of light with the camera lens, multiple scattering in outdoor scenes, chromatic dispersion, interaction between polarized light and certain materials, ... and many, many more phenomena. So rather than try to model each of those physical lighting effects in realtime, it would be wonderful to have a "RNG()" shader function to simply add a smidgen of unpredictability to our realtime rendering techniques. The closer your final image resembles nature, the better it looks --- and nature is many things, but she is not a perfectly smooth BRDF lighting model! So yeah... It would be frickin' sweet to have this RNG on a GPU.