Skip to content
  • Home Home Home, current page.
  • Moments Moments Moments, current page.

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
RichFelker's profile
Rich Felker
Rich Felker
Rich Felker
@RichFelker

Tweets

Rich Felker

@RichFelker

Yeah, I do @musllibc, FOSS & infosec stuff. But now is not the time for a mostly-/only-tech Twitter feed.

musl-libc.org
Joined March 2014

Tweets

  • © 2018 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
      Replying to @gsuberland

      You can mix as much non-random, predictable data as you like into this. As long as you have one good source of entropy, it's safe.

      2 replies 0 retweets 5 likes
    2. Rich Felker‏ @RichFelker 25 Mar 2017
      Replying to @gsuberland

      True only as long as the provider of the non-random, predictable data can't see the state. If it can, you're screwed.

      1 reply 0 retweets 0 likes
    3.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
      Replying to @RichFelker

      That's only the case when you xor the state. When you append it, it doesn't matter.

      2 replies 0 retweets 0 likes
    4.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
      Replying to @gsuberland @RichFelker

      I assume you're referring to Linux's ill-advised implementation of directly xor'ing RDRAND output into the kernel entropy pool.

      1 reply 0 retweets 0 likes
    5. Rich Felker‏ @RichFelker 25 Mar 2017
      Replying to @gsuberland

      Yes that was one example I had in mind, but I'd be cautious about assuming more subtle ones don't exist.

      1 reply 0 retweets 0 likes
    6.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
      Replying to @RichFelker

      The key part here is that a transistor-level RDRAND output that just mirrors the existing pool is fairly feasible.

      2 replies 0 retweets 0 likes
    7.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
      Replying to @gsuberland @RichFelker

      Whereas the amount of logic required to attack a hash-based system would be much larger and much more obvious to anyone looking.

      1 reply 0 retweets 0 likes
    8. Rich Felker‏ @RichFelker 25 Mar 2017
      Replying to @gsuberland

      Not thinking purely silicon. Something heartbleed-like could allow more advanced attacks.

      1 reply 0 retweets 0 likes
    9.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
      Replying to @RichFelker

      Heartbleed was a memory disclosure limited to the target process. It wouldn't be affected by entropy mixing choice.

      2 replies 0 retweets 0 likes
    10. Rich Felker‏ @RichFelker 25 Mar 2017
      Replying to @gsuberland

      Heartbleed-like = something providing read-only access to memory containing state (not necessarily kernel, e.g. arc4random-like)

      2 replies 0 retweets 0 likes
      Rich Felker‏ @RichFelker 25 Mar 2017
      Replying to @RichFelker @gsuberland

      If you can steal the state, there's an opportunity to try to provide bad data to be mixed, with vast computing resources.

      6:02 PM - 25 Mar 2017
      1 reply 0 retweets 0 likes
        1. New conversation
        2.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
          Replying to @RichFelker

          If you can steal the state then you can predict random numbers until the next reseed anyway. But yes, that's why you use a hash.

          1 reply 0 retweets 0 likes
        3.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
          Replying to @gsuberland @RichFelker

          If you control all the entropy going in then you win anyway. If you control all but a single good entropy source then you lose.

          1 reply 0 retweets 0 likes
        4.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
          Replying to @gsuberland @RichFelker

          to break you'd need a break in H such that H(s+u+q) is predictable, where u is an unknown, s is known & q is a value you picked.

          1 reply 0 retweets 0 likes
        5.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
          Replying to @gsuberland @RichFelker

          s being the state, u being the unpredictable output of a good entropy source, and q being bad entropy from you.

          1 reply 0 retweets 0 likes
        6.  🎃 Graham Spookyland  🎃 [Polynomial^DSS]‏ @gsuberland 25 Mar 2017
          Replying to @gsuberland @RichFelker

          Or worse, you'd need to make H(H(s+u)+q) predictable. Which would be a ludicrous break of the hash.

          0 replies 0 retweets 0 likes
        7. End of conversation

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2018 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Cookies
        • Ads info