Pseudorandom number generators | Computer Science | Khan Academy

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  • Опубліковано 30 вер 2024

КОМЕНТАРІ • 233

  • @DipperSlipper
    @DipperSlipper 5 років тому +1087

    Great Video! I got here from Angela's Course.

  • @ThandaTaco4505
    @ThandaTaco4505 3 роки тому +170

    this video is trippy af.

  • @TVVDINAKARAN
    @TVVDINAKARAN 2 роки тому +42

    Damn this shit was taking me to the 90's vibe, it was wa more than a tutorial...

  • @swapnilchaturvedi821
    @swapnilchaturvedi821 4 роки тому +81

    Great video,Got its link from Angela's course

  • @sadijdhakal
    @sadijdhakal 6 років тому +88

    I felt like I watched those 1960s tutorial video. lol

  • @ramakrishnakadiyala3014
    @ramakrishnakadiyala3014 3 роки тому +29

    The background music felt like a thriller movie 😰

  • @mkerm3875
    @mkerm3875 4 роки тому +19

    whats with the song in the background bro its just math math itn't scary ... well it is but still

  • @Nico-ny2om
    @Nico-ny2om 8 років тому +33

    Quantum computers are coming, we're damned

  • @mrrakeshmohansinghnegi248
    @mrrakeshmohansinghnegi248 2 роки тому +8

    I like the cosmic horror vibes

  • @TheEgg185
    @TheEgg185 5 років тому +24

    4:12 what??? Shift? Pages? This part of the video made absolutely no sense.

    • @baatar
      @baatar 5 років тому

      Yeah, I was lost too.

    • @hugobarrazavizcarra482
      @hugobarrazavizcarra482 5 років тому

      @@baatar Explanation please.

    • @baatar
      @baatar 5 років тому

      @@hugobarrazavizcarra482 "If Alice generates a truly random sequence of 20 (shifts?)" No idea what he's saying here. 4:05

    • @seras.gulser6962
      @seras.gulser6962 5 років тому +6

      I think "shift" means the number times she throws the dice to make her sequence. Dice here is a dice-26 dice, hence 26 to the power of 20.

    • @PvblivsAelivs
      @PvblivsAelivs 4 роки тому +13

      It makes more sense if you have seen some of the other videos. He is talking about a stream cipher where each letter is shifted a number of places in the alphabet to produce the encrypted message. The pages refer to a stack in which each page refers to a possible sequence of shifts for each of 20 letters in a message.
      Admittedly, the videos don't stand very well independently.

  • @oatscurry
    @oatscurry 5 років тому +33

    I just realized that since this video is in a series, it's probable that Khan Academy defined "shifts" in an earlier video. I remember watching these last year and believe that this may be the case.

    • @Gersberms
      @Gersberms 11 місяців тому +1

      Came here to ask the same thing, "why is he talking about shifts?"

  • @Athenas_Realm_System
    @Athenas_Realm_System 8 років тому +28

    in cryptographically secure pseudo-random number generators such as the /dev/random and /dev/urandom on Unix machines, it constantly takes up new seeds to prevent anyone known the state of the generator at any one time fully. It usually uses stuff like block ciphers and hashes to take essentially random input like keystrokes, and hardware interrupt timing to continually shuffle the output to keep it as secure as possible for generating keys and stuff for encryption such as using a https connection. For CSPRNGs it is required to pass tests for statistical randomness as you wouldn't want to use a encryption key even for a one time pad that was a very simple number that wasn't random at all.

    • @kebekbutcher
      @kebekbutcher 4 роки тому +2

      Don't think you are safe behind cryptography, but the more bits involved, the more secure exponentially... but with super computer that government can use, 1024bits encryptions is pretty safe probably 512bits is enough for the effort needed for what you are hiding, if you don't know how computer encryption works, I invite you to look for basic encryption videos about it. This video is only about RNG in computing... It has nothing to do with RNG in encryptions...

    • @SuperJosba
      @SuperJosba 2 роки тому

      me too :)!

  • @sumabich721
    @sumabich721 2 роки тому +2

    Angela brought me here

  • @ryzenofficial4700
    @ryzenofficial4700 Рік тому +2

    I'm here because of Dr. Angela Yu's web development course on udemy.

  • @ishaanbhalla396
    @ishaanbhalla396 3 роки тому +7

    damn I feel like doing shrooms and watching this again

  • @网于睿
    @网于睿 3 роки тому +8

    what does the word "shift" mean in this video? "if Alice generates a truly random sequence of 20 shifts, it's equivalent to a uniform selection from the stack of all possible sequences of shifts."

  • @thanasisthanasistha
    @thanasisthanasistha 7 місяців тому +3

    Great video! Ι 've got this link from Angela's course!

  • @atikshaikh3121
    @atikshaikh3121 4 роки тому +7

    Got here from Angela's Course

  • @B44-y5i
    @B44-y5i 3 роки тому +2

    why was this video so scary

  • @lucacommonjay7894
    @lucacommonjay7894 5 років тому +6

    I like this video as much as Kanye loves Kanye

  • @xXsniperleoXx
    @xXsniperleoXx 3 роки тому +4

    we call things random because we don't see any links, that doesn't mean there necessarily aren't. maybe randomness is subjective

  • @subhamrai4908
    @subhamrai4908 3 роки тому +2

    Who is here from Angela's course? 😂

    • @manikandand4439
      @manikandand4439 3 роки тому +1

      Me 👐

    • @uzairali7420
      @uzairali7420 3 роки тому +1

      @@manikandand4439 i download this course from random website this course is old for me but its free
      there is no bootstrap 5 or flexbox

  • @watchmeexplode
    @watchmeexplode 2 роки тому +3

    This video is creepy 😶

  • @novanoskillz4151
    @novanoskillz4151 3 роки тому +3

    Angela sent me here!

  • @halimaa213
    @halimaa213 5 років тому +7

    This video was uncomfortable. But I had to watch as it was recommended by a javascript course I'm taking. Thanks!

  • @MrPicklepod
    @MrPicklepod 4 роки тому +4

    I didn't think this video was going to be what it is

  • @yalongli3993
    @yalongli3993 4 роки тому +5

    Great to know the magic of random number generation!

  • @will-se7wj
    @will-se7wj 2 роки тому +1

    the music is so creepy lol

  • @yuyhero
    @yuyhero 3 роки тому +4

    This is good stuff. Not even being taught about this on my CS class

  • @codervipersan4321
    @codervipersan4321 3 роки тому +2

    I also from angela yu course

  • @pankajthapaliya2336
    @pankajthapaliya2336 3 роки тому +3

    Thank you khan academy !
    got here while learning random module in python

  • @indiansoftwareengineer4899
    @indiansoftwareengineer4899 5 років тому +4

    Nice video, truly educational.
    Love you Khan academy.

  • @agstechnicalsupport
    @agstechnicalsupport 5 років тому +4

    Great video explaining random and pseudo random number generation.

  • @yyin3061
    @yyin3061 3 дні тому

    Great video! Ι 've got this link from Angela's course! : )

  • @pkpcmu
    @pkpcmu 4 роки тому +2

    that dong noise in last two minutes of this ruined it for me - sheer noise!

  • @SHaKoB0_0
    @SHaKoB0_0 2 роки тому +2

    holy shit never knew that I needed this video that much

  • @Obliviouse27
    @Obliviouse27 4 місяці тому

    So from what I understand by using the 3 middle numbers after doing 2 /3 actions and repeating we are saving ourselves some time to find matching sequence.
    While multiplying these gets you around 10000 unites of numbers which is not as big as million it some how saves time and I suppose makes the probability of matching the numbers fairly moderated.

  • @jonrutherford6852
    @jonrutherford6852 5 місяців тому

    Very nice exposition. I did, though, get a chuckle from the bike-lock analogy. As thousands of cyclists know by now, a lock such as the one shown is not safe even for eight seconds, let alone eight hours. (Hint: chain cutter.)

  • @shagunprasad4592
    @shagunprasad4592 7 місяців тому +1

    this video literally reduces william stalling's entire sub section on PRNGs and TRNGs to a 6 minute video. absolutely mind blowing !!

  • @serious6037
    @serious6037 Рік тому +1

    Why is this so mystical lmao

  • @abdullahAboelkhair
    @abdullahAboelkhair 2 роки тому +3

    Mindblowing!

  • @Vineet0078
    @Vineet0078 Рік тому +1

    I cant understand anything, am i dumb?

  • @neriyacohen7805
    @neriyacohen7805 2 роки тому

    Are you nuts? Worst video of khan. The noise drived me crazy. Why do it for knowledge seekers( ADHD aside?)
    If you dont remove the noise at the very least add scratching noises,screams and breaking glass

  • @akkienergy
    @akkienergy 14 днів тому

    Got here from Angela's Python course. Great video indeed!

  • @nerfking1761
    @nerfking1761 6 місяців тому

    Amazing video! Really helped me to understand random number generators. Got reference from Angela Yu’s course on udemy

  • @Stormbolt_1
    @Stormbolt_1 24 дні тому

    This makes me feel like I'm watching a Dharma video from LOST

  • @zacharysun01
    @zacharysun01 3 місяці тому

    Joe Grand has a video where he uses the logic of Pseudorandom number generators to crack open a 3 million dollar crypto wallet.

  • @blackhole1617
    @blackhole1617 Рік тому

    I'm here from Angel's course

  • @tapiiee
    @tapiiee 6 місяців тому

    I always wondered how Minecraft seeds worked, this was really interesting

  • @bengalbaby6118
    @bengalbaby6118 4 роки тому +1

    Isn't Bitcoin Blockchain set up something like this? Where to find a key, or a matching key, numbers must be ran, and ran, and ran, to get what the miner is looking for? Or they have to keep running numbers for the permission to claim that posting? Just curious.

  • @patricial.321
    @patricial.321 Рік тому +1

    You guys just saved my presentation due in 4 days

  • @ghanisthsingh347
    @ghanisthsingh347 Місяць тому

    I see, a lot of us are already here from Angela's course 😂😂😂

  • @yungtripoli
    @yungtripoli 11 місяців тому

    i was high watching this and it gave me so much anxiety

  • @ShuAbLe
    @ShuAbLe 2 роки тому +1

    Wow, that is a cliff hanger ending!

  • @shreyasahu481
    @shreyasahu481 4 роки тому +1

    Got scared and closed the tab.

  • @RichardinSA
    @RichardinSA Місяць тому

    Like woah man... thanks for the trip!

  • @majorramsey3k
    @majorramsey3k 7 років тому +2

    I used 41 and got 4116814624384470560250062538447056025006253844etc
    Although I ended up with a repeating sequence, I did not encounter the seed of 41 repeating itself. Did I do something wrong?

    • @lucianbicsi1636
      @lucianbicsi1636 6 років тому +4

      No. It doesn't have to start repeating at the initial seed.

    • @majorramsey3k
      @majorramsey3k 6 років тому +1

      Thanks!

    • @sbhtkapps364
      @sbhtkapps364 6 років тому +3

      All it takes for the sequence to repeate itself is that one seed that has already been used show up again and then the sequence will start to repeat itself, that's why he said that for 2 digit it can go at most to 100 and not always

    • @noorameera26
      @noorameera26 3 роки тому +1

      @@lucianbicsi1636 thank you too!

  • @skropp9339
    @skropp9339 6 років тому +1

    While word size dependence is true for linear congruential generators, there are plenty of random number generators whose period is independent of the word size; as an example, the mersenne generator or R250. What you are saying is accurate but it comes across as if you are saying that LCG is the only algorithm.

  • @chandanchandu4914
    @chandanchandu4914 3 місяці тому

    Nan Anthu obirayan kalaa kee hogidhee 🥴

  • @hotmandead1
    @hotmandead1 7 років тому +2

    I got here from a book on C programming

  • @MotoMoto-ym3cp
    @MotoMoto-ym3cp 9 місяців тому

    The examples for true randomness given in the beginning of the video are not rally randomness, but chaotic distributions. Waves, pepples at the beach, white noice are not indeterministic. As part of the macroscopic world they are deterministic albeit not computable. All true randomness comes only from quantum effects like nuclear decay. Only the quantum space provides randomness. The rest is either pseurdorandom or chaotic but deterministic

  • @AiSings163
    @AiSings163 10 місяців тому

    Well We are Living in a world where all the possibilities of guessing a pseudorandom is no more securty with quantam computing its now possible...⭐⭐

  • @followrajah7743
    @followrajah7743 7 місяців тому

    Dr Angela Yu brought me here

  • @francisdeleon4672
    @francisdeleon4672 2 роки тому +1

    great production!

  • @GFD_VIDEOS
    @GFD_VIDEOS Рік тому

    All casinos both online and land based use PRNG’s to insure profitability at the expense of gamblers being fooled to believe that they are actually playing !

  • @ludwig8384
    @ludwig8384 4 місяці тому

    Angela Yu brought me here.

  • @seckomatikreloaded5283
    @seckomatikreloaded5283 2 роки тому

    This video is creepy, like one of those Dharma Initiative orientation videos from LOST

  • @alexhichamk6630
    @alexhichamk6630 4 місяці тому

    D.Angela is the reason

  • @kritisingh3194
    @kritisingh3194 3 роки тому +3

    The end scared me, jeez. But hey, great video! :)

  • @mathlead956
    @mathlead956 Рік тому

    What if you make random numbers from nonrepeating things like Penrose tilings

  • @ThakurCoder77
    @ThakurCoder77 8 місяців тому

    This video is educational and trippy at the same time😵‍💫

  • @LatelierdArmand
    @LatelierdArmand 2 місяці тому

    trippy edit love it

  • @luls9000
    @luls9000 5 років тому

    What happens at 2:28 ??? The second output is 529, not 587... Wtf???

  • @openroomxyz
    @openroomxyz 3 роки тому +1

    Love it

  • @JeffPittman
    @JeffPittman 3 роки тому +1

    DNA @ 3:04

  • @jsc3417
    @jsc3417 3 роки тому

    I dump plenty seeds into the toilet each day.

  • @youtubeshortsmix2356
    @youtubeshortsmix2356 Рік тому

    from udemy

  • @singerbabe82
    @singerbabe82 5 років тому

    i hate the background music

  • @mdraihan1067
    @mdraihan1067 5 років тому +2

    plzz stop the background sound

  • @michaelmueller5211
    @michaelmueller5211 3 роки тому

    so much clearer! ty! 😇

  • @TheNetflixGamer
    @TheNetflixGamer 3 роки тому

    Okay okay sick

  • @Mecharnie_Dobbs
    @Mecharnie_Dobbs Рік тому

    Very pretty

  • @shahryarhabibi7187
    @shahryarhabibi7187 3 роки тому

    thanks

  • @prashoonbhattacharjee8211
    @prashoonbhattacharjee8211 4 роки тому

    Good tutorial👍!!

  • @pradyumnakubear5366
    @pradyumnakubear5366 4 роки тому

    Nice

  • @ponyatnoeit169
    @ponyatnoeit169 3 роки тому

    Интересно😵

  • @TheEgg185
    @TheEgg185 5 років тому +1

    For every, I don't know, 10,000 calculations, why don't we start taking MORE than just the middle 3 digits and make THAT be the new seed??? Problem solved, no?

  • @pineapplewhatever5906
    @pineapplewhatever5906 Рік тому

    1:12 I don't think machines are deterministic.
    I was running a program that backed up to a file each minute. I loaded the most recent backup into it. Power went off. Tried loading the backup again. It was BLANK. Inspected the backup with a hex editor: It was all zeroes. Inspected the code of the program: The program could not have written the zero byte into the file. Clearly, if the machine were deterministic, this could not have happened.