lol im so random!

Presented at !!con (http://bangbangcon.com) 2016

Randomness has many applications in computing ranging from cryptography and statistics to generative art and simulation, but where does randomness come from? When you ask for a random number from your system, how truly random is it?

This talk will explore randomness in software practice in a variety of contexts. Touching on sources of entropy, pseudo-random number generation, and what it means to be cryptographically secure, this talk will explore both the algorithms and the APIs that supply us with random numbers. This talk will also cover the mechanisms for testing and verifying statistical randomness. Interspersed seemingly randomly throughout will be some great examples of bots, games, and generative art that use randomness and procedural generation in creative and unusual ways. You will come away from this high-level overview with a newfound sense of respect and awe for the humble Math.random().

https://mobile.twitter.com/markwunsch/timelines/729376400218701824

Transcript

1. lol
   im so random!
   @markwunsch
   

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2. Math.random()
   

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3. https://xkcd.com/221/
   

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4. George Raft

   Scarface, 1932
   

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5. http://www.rand.org/pubs/monograph_reports/MR1418.html
   

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7. John von Neumann
   Various Techniques Used in Connection With Random Digits
   “Any one who considers arithmetical methods
   of producing random digits is, of course, in a
   state of sin. For, as has been pointed out
   several times, there is no such thing as a
   random number — there are only methods to
   produce random numbers, and a strict
   arithmetic procedure of course is not such a
   method.”
   

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8. Pseudorandom
   Number Generator
   (PRNG)
   
   

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9. Animate[ListPlot[BlockRandom[
   SeedRandom[seed, Method ! “MersenneTwister”];
   RandomReal[1, 10000]]],
   {seed, 1, 100, 1}]
   

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10. (rand)
    

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11. (defn rand
    “Returns a random floating point
    number between 0 (inclusive) and n
    (default 1) (exclusive).”
    ([] (. Math (random)))
    ([n] (* n (rand))))
    clojure.core
    

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12. public static double random()
    Returns a double value with a positive sign, greater than or equal to
    0.0 and less than 1.0. Returned values are chosen pseudorandomly
    with (approximately) uniform distribution from that range.
    When this method is first called, it creates a single new
    pseudorandom-number generator, exactly as if by the expression
    new java.util.Random()
    This new pseudorandom-number generator is used thereafter for
    all calls to this method and is used nowhere else.
    java.lang.Math
    

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13. Mary Rose Cook
    A practical introduction to functional programming
    https://maryrosecook.com/blog/post/a-practical-introduction-to-functional-programming
    “Functional code is characterized by one thing:
    the absence of side effects. It doesn’t rely on
    data outside the current function, and it
    doesn’t change data that exists outside the
    current function.”
    

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14. random :: (RandomGen g, Random a) => g -> (a, g)
    

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15. > import System.Random
    > random (mkStdGen 42) :: (Int, StdGen)
    (-3900021226967401631,2060101257 2103410263)
    

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16. Tell’s Knabe
    From the Schiller Gallery, 1859
    

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17. Property-Based Testing
    QuickCheck & its scions

    http://www.cse.chalmers.se/~rjmh/QuickCheck/
    Gary Fredericks — Purely Random

    from Clojure/West 2015

    https://www.youtube.com/watch?v=u0t-6lUvXHo
    

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18. The

    Mersenne 

    Twister
    
    

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19. 219937-1
    

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20. 219937-1
    the period
    

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21. “PRNGs are currently implemented as a modified
    Mersenne Twister with a period of 2**19937-1” 

    http://ruby-doc.org/core-2.2.2/Random.html
    “Python uses the Mersenne Twister as the core
    generator. It produces 53-bit precision floats and
    has a period of 2**19937-1.” 

    https://docs.python.org/3/library/random.html
    “Random number generation in Julia uses the
    Mersenne Twister library via MersenneTwister
    objects.” 

    http://docs.julialang.org/en/release-0.4/stdlib/numbers#random-numbers
    

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22. TIFU by using Math.random()

    https://medium.com/@betable/tifu-by-using-math-random-f1c308c4fd9d
    There’s Math.random(), and then there’s Math.random()

    http://v8project.blogspot.com/2015/12/theres-mathrandom-and-then-theres.html
    

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23. http://stat.fsu.edu/pub/diehard/
    

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24. cf.
    TestU01

    http://simul.iro.umontreal.ca/testu01/tu01.html
    dieharder

    https://www.phy.duke.edu/~rgb/General/dieharder.php
    

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25. “The Mersenne Twister … is
    completely unsuitable for
    cryptographic purposes.”
    https://docs.python.org/3/library/random.html
    

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26. “Mersenne Twister is not
    cryptographically secure.”
    http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
    

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27. cryptographically
    secure
    

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28. Cryptographically
    Secure Pseudorandom
    Number Generator
    (CSPRNG)
    
    

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29. Achillea millefolium
    Köhler’s Medizinal-Pflanzen, 1887
    

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30. Yarrow
    Bruce Schneier and John Kelsey
    https://www.schneier.com/cryptography/yarrow/
    

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31. The

    Entropy
    Device
    

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32. /dev/random
    man 4 random
    

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33. function lookbusy() { cat /dev/urandom | od -An; }
    

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34. 101262 024567 163231 107002 047500 141110 112373 100363
    141204 177347 033443 153461 150705 005261 075113 041430
    057531 072242 066770 001374 110052 004716 160523 064356
    127045 113127 072433 031735 146001 040647 105205 104464
    010021 174056 072621 047566 041173 074062 063702 142662
    012703 064566 004331 124752 002455 051065 171176 014151
    024462 007765 036437 057554 111072 070733 014741 102411
    117460 057656 073073 127016 124774 015743 013005 153673
    171613 152444 166643 141710 150477 054502 150175 055630
    045701 024774 074654 021546 164660 127465 075035 027547
    032112 110437 170726 052324 112261 011234 163423 053520
    042643 123732 016343 143734 003171 047752 161731 104761
    106311 014712 162121 020272 150470 046124 156427 104625
    172660 135352 034330 164771 076535 031660 146333 030455
    041511 072500 017333 102715 074317 065237 075131 054032
    001217 044045 046220 073062 021534 060345 065446 034237
    130226 034734 061603 022274 133362 066144 103771 055055
    073664 162725 013732 123243 144705 061310 106532 161743
    002362 002610 111577 071633 124030 024525 146333 101235
    160420 030052 002761 175720 125564 017030 007503 120511
    124152 032335 041561 057646 177455 030002 010667 074013
    

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35. $ expr $RANDOM % 6 + 1
    $ awk ‘BEGIN { srand(); print 1 + int(rand() * 6); }’
    $ cat /dev/urandom | hexdump -v -e '/1 "%u\n"' | awk
    '{ split("0,2,4,5,7,9,11,12",a,","); for (i = 0; i
    < 1; i+= 0.0001) printf("%08X\n",
    100*sin(1382*exp((a[$1 % 8]/12)*log(2))*i)) }' |
    xxd -r -p | aplay -c 2 -f S32_LE -r 16000
    http://blog.robertelder.org/bash-one-liner-compose-music/
    

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36. 10 PRINT CHR$(205.5+RND(1)); : GOTO 10
    http://10print.org
    

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37. Allegory of Chance
    Frans Francken the Younger, 1627
    

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38. ^D
    

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