Chacha Cipher - Computerphile

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  • เผยแพร่เมื่อ 23 พ.ย. 2024

ความคิดเห็น • 294

  • @U014B
    @U014B 3 ปีที่แล้ว +1245

    While not the fastest or most robust cipher, many computer scientists confidently assert the ChaCha as being real smooth.

    • @franatrturcech8484
      @franatrturcech8484 3 ปีที่แล้ว +40

      See whatcha did there

    • @mayabartolabac
      @mayabartolabac 3 ปีที่แล้ว +16

      that's a real smooth joke

    • @techieadam5031
      @techieadam5031 3 ปีที่แล้ว +11

      If AES was broken that would be a turnaround

    • @korpos8833
      @korpos8833 3 ปีที่แล้ว +8

      hahahahhaa, how Dr. Mike explains things is just amazing!. I can barely hold my cup of tea while enjoying his lectures.

    • @microcolonel
      @microcolonel 3 ปีที่แล้ว +10

      To completely miss the point though, ChaCha's standard round count (20) makes its security margin significantly more than AES. To have a similar margin, eight rounds of ChaCha should be sufficient.

  • @philipschloesser
    @philipschloesser 3 ปีที่แล้ว +564

    In my cryptology lecture, there were two lectures given by a guest lecturer, he was introduced by name, but nothing more. He talked a bit about the history and the ideas behind modern symmetric cryptography (we had been doing RSA and prime stuff before that). He mentioned ChaCha20 and Poly-1305, but mostly talked about DES and AES... Until: "Oh, and maybe I should mention that I am actually the designer of ChaCha20 and Poly-1305." Name of the guest lecturer? Daniel J Bernstein.

    • @stevefan8283
      @stevefan8283 3 ปีที่แล้ว +52

      Lucky you, he also designed Curve25519 which is an alternative to RSA and is quickly accelerated in adopting for the likes of its smaller key sizes (128-bit curve25519 = 2048-bit RSA)

    • @sundhaug92
      @sundhaug92 3 ปีที่แล้ว +2

      Too bad he's an asshole

    • @Spongezipper
      @Spongezipper 3 ปีที่แล้ว +7

      I guess we were in the same lecture then. It was after the lecture that I looked him up and discovered that he was quite influential indeed.

    • @y8fpe
      @y8fpe 3 ปีที่แล้ว +5

      @@sundhaug92 no that's you mate

    • @sundhaug92
      @sundhaug92 3 ปีที่แล้ว

      @@y8fpe I linked my source, but I'm not seeing it here atm

  • @kigtod
    @kigtod 3 ปีที่แล้ว +124

    I can think of another 16 character constant string that might have been appropriate: ‘DanielJBernstein’. If artists can sign beautiful creations, why not mathematicians?

    • @spinner4148
      @spinner4148 3 ปีที่แล้ว +33

      When I saw it was a 16 character string I thought it was going to be "chacharealsmooth" and that's how it got its name. Slightly disappointed!

    • @scheimong
      @scheimong 3 ปีที่แล้ว +8

      There will probably be people talking trash and complaining about something something egotistical something [insert your profanity of choice]. So I respect his choice.
      But on the other hand, maybe he could learn a thing or two from Linus Torvalds on dealing with morality disagreements...

    • @heh2393
      @heh2393 3 ปีที่แล้ว +8

      @@scheimong "Nvidia, ... F*@€ you!"

  • @oafkad
    @oafkad 3 ปีที่แล้ว +228

    Wait? He has legs? I just assumed he was a torso attached to a server simulating humanity.

  • @TrojanHell
    @TrojanHell 3 ปีที่แล้ว +139

    Mike: KSG is not a real thing
    My brain: "Kerbal Space Grogram"

  • @_..---
    @_..--- 3 ปีที่แล้ว +302

    "someone incredibly smart like me", lmao humble Mike

    • @ethansimmons82
      @ethansimmons82 3 ปีที่แล้ว +5

      but is he wrong...

    • @RedwoodRhiadra
      @RedwoodRhiadra 3 ปีที่แล้ว +20

      @@ethansimmons82 I'm now half-expecting the next issue of the Journal of Cryptology to publish a new paper by Mike...

    • @digitalairaire
      @digitalairaire 3 ปีที่แล้ว +4

      1:43

    • @khronos142
      @khronos142 3 ปีที่แล้ว +4

      now we all waiting for that paper drop. you know Mike just bought hella cha cha stocks too

    • @keyboard_toucher
      @keyboard_toucher 3 ปีที่แล้ว +3

      Let's put aside the ludicrousness of that

  • @BerkDDemir
    @BerkDDemir 3 ปีที่แล้ว +7

    So good.
    Tiny nit: in the animations XOR is denoted with circled times ⊗ but the operator for XOR is circled plus ⊕.

  • @0LoneTech
    @0LoneTech 3 ปีที่แล้ว +16

    Depending on your logic family, you may still have to do extra work to make this constant time or power. Mainly because carry chains will take different time to complete depending on values. But for a typical synchronous processor with constant clock rate, it's constant time.

  • @juanjocg1870
    @juanjocg1870 3 ปีที่แล้ว +100

    There's Mike on the background.
    *me:* click

  • @risv
    @risv 3 ปีที่แล้ว +41

    Oh boy, it's Dr. Pound back again!

    • @joonasfi
      @joonasfi 3 ปีที่แล้ว +4

      Aww yiss, take me to Pound town

    • @spicybaguette7706
      @spicybaguette7706 3 ปีที่แล้ว

      Always my favourite videos

  • @marioh9926
    @marioh9926 3 ปีที่แล้ว +28

    Very illustrative, thanks again. Mike, could you do a video talking about SHA-3 or the Keccak construction? It would be very helpful.

    • @stromboli183
      @stromboli183 3 ปีที่แล้ว +3

      Yes I’d love to see this as well 👍

  • @georgebizos944
    @georgebizos944 3 ปีที่แล้ว +147

    "Let's not have me dance on the internet; people don't need to see that"
    I disagree; people definitely need to see that.

    • @MisterOA
      @MisterOA 3 ปีที่แล้ว

      Exactly! We would love to see it!

  • @Brainstorm4300
    @Brainstorm4300 3 ปีที่แล้ว +9

    I looked into chacha last semester for a project, ended up not using it but I'm happy our fav prof made a video on it! 😊

    • @Brainstorm4300
      @Brainstorm4300 3 ปีที่แล้ว +2

      I have a question, on the receiver's side, since there's no guarantee that they'll receive the blocks in order, how does it determine the block number for decryption?

    • @andrewanyplace
      @andrewanyplace 3 ปีที่แล้ว +10

      @@Brainstorm4300 The transport layer protocol such as Transmission Control Protocol (TCP) would deal with putting the message in order before the decryption is performed.

    • @Brainstorm4300
      @Brainstorm4300 3 ปีที่แล้ว +1

      @@andrewanyplace Ah of course! Thank you!

  • @andydalytube
    @andydalytube 3 ปีที่แล้ว +130

    Man, 'nonce' is a really unfortunate term to use for 'number used once' 😶🔫

    • @devildown55
      @devildown55 3 ปีที่แล้ว +9

      thats exactly what i thought haha

    • @faielgila7375
      @faielgila7375 3 ปีที่แล้ว +9

      Should be nuonce...
      oh wait

    • @nuthinnew
      @nuthinnew 3 ปีที่แล้ว +4

      I've got a non techie friend who is really sensitive to stuff like that, when I told him he was disgusted 🙃

    • @LoganKearsley
      @LoganKearsley 3 ปีที่แล้ว +12

      @@nuthinnew Wait, explain: what offensive thing do I not know about?

    • @WilcovanBeijnum
      @WilcovanBeijnum 3 ปีที่แล้ว +14

      @@LoganKearsley According to the urban dictionary it's slang for paeophile. I did not know about this meaning of nonce either

  • @mgostIH
    @mgostIH 3 ปีที่แล้ว +5

    Ohh finally! This one is my favourite, far simpler than AES but even faster (without hardware acceleration), if you are implementing any symmetric cipher (or crypto RNG) yourself go for this!

    • @oscarsmith3942
      @oscarsmith3942 3 ปีที่แล้ว +2

      Counter point: If you are implementing a symmetric cypher yourself, don't.

    • @mgostIH
      @mgostIH 3 ปีที่แล้ว +8

      @@oscarsmith3942 ChaCha is far simpler and without risks of side attacks compared to AES, it can already do wonders as a crypto quality RNG with just 8 rounds! I'm more in favour of cryptography that's simpler and harder to screw up rather than forbidding everyone from ever getting into the field, practice is important and not every project has dire consequences if gotten wrong

  • @AlexanderMichelson
    @AlexanderMichelson 3 ปีที่แล้ว +5

    Thank you, Dr Mike Pound!

  • @447flamethrower
    @447flamethrower 3 ปีที่แล้ว +13

    Yes he's my favorite prof!

  • @lawrencedoliveiro9104
    @lawrencedoliveiro9104 3 ปีที่แล้ว

    3:51 When I were a stoont, we had blackboards which were wraparound flexible sheets on rollers. So you just pulled on them to roll on to a new section. Eventually you wrapped round again to the part you previously wrote on, of course, so you had to erase it anyway, but in the meantime it could be left visible as reference.

  • @filipo4114
    @filipo4114 3 ปีที่แล้ว +32

    Brady, a youtuber: "It's Instagram format"
    Smart person not knowing what's he talking about: "yeah, yeah, yeah"
    10:20

  • @No0utlet
    @No0utlet 3 ปีที่แล้ว +14

    Maybe it's cause I was watching at 2x speed, but as a parent I felt about 95% confident that Dr. Pound has to pee.

  • @Nyawful
    @Nyawful 3 ปีที่แล้ว +1

    Awesome one again! Please add a playlist with only Mike videos!

  • @erichobbs4042
    @erichobbs4042 3 ปีที่แล้ว +7

    The ludicrousness of that...
    Mike so has that paper ready to publish.

  • @MegaRad666
    @MegaRad666 3 ปีที่แล้ว +11

    I think if I ever go back to school, I would love to study cryptography. Great explanation Dr. Pound!

  • @TechyBen
    @TechyBen 3 ปีที่แล้ว +14

    I can see Mike secretly hopes AES is broken/superseded, so he can tell everyone to go "do the Chacha" for his job. XD

    • @CharlesHepburn2
      @CharlesHepburn2 4 หลายเดือนก่อน

      AES has stood as king of the hill for 27 years now… with the smartest people on earth trying to break it. So don’t hold your breath on this happening any time soon.

    • @TechyBen
      @TechyBen 4 หลายเดือนก่อน +1

      @@CharlesHepburn2 Oh, I totally get that... he'd just "hope" so he can go home early that day. ;)

  • @thealliedhacker
    @thealliedhacker 3 ปีที่แล้ว +2

    Most of this seems like it's just describing the process for converting any hash function into a stream cipher. The question becomes why use this as the hash function over something like SHA-256. This seems like it needs to be just as secure as any hash algorithm, because I assume one of the attacks we're protecting against is a known-plaintext block giving await the key for the rest of the stream, which would be possible if you reversed the hash... I assume this is faster than SHA-256, but speed can be a bad thing for hash algorithms, since it makes brute force reversal easier.

    • @espadrine
      @espadrine 3 ปีที่แล้ว

      A few misconceptions:
      1. A hash function has multiple meanings. In a hash table, for instance, all you expect is diffusion. The construct you expect for a *cryptographic* hash function is called a collision-resistant compression function. In the case of ChaCha, you don’t need that, because you don’t care about compression nor about collision resistance. Just diffusion.
      2. Cryptographic hashes do try to be as fast as possible (while offering collision resistance). But their properties are only useful when the input is random. Thus hashes cannot be used for low-entropy inputs (less than 1 bit of entropy per bit), such as passwords. For those, we need to purposefully slow down a brute-force attack, by using a specific KDF such as Argon2.

  • @RedstoneNinja99
    @RedstoneNinja99 3 ปีที่แล้ว +1

    Have you seen the peer to peer software Briar? Looks pretty cool for digital privacy especially journalists in the field because it supports communication over bluetooth and wifi, its all end to end encrypted and when connected to internet everything is routed through tor. I would really love to see Mike do a video on that to signal boost it hopefully to people that really need it!

  • @bauerfischer3030
    @bauerfischer3030 ปีที่แล้ว +1

    I looked it up you did not published a Paper the next day!

  • @mgancarzjr
    @mgancarzjr 3 ปีที่แล้ว +4

    Just read about it yesterday while researching AES. Neat.

  • @indiansoftwareengineer4899
    @indiansoftwareengineer4899 3 ปีที่แล้ว

    Thanks for bringing smiles to videos, and sir you are really "SMART",
    Love from India....
    Thanks for free sharing knowledge...

  • @hassansyed5661
    @hassansyed5661 6 หลายเดือนก่อน

    Every cipher which is using look up tables for example AES (Rijndael) are suspectable to side channel timing attacks because they take variable time when doing look up however this is not the case with Chacha 20 because it takes constant time for XOR, Addition and Rotate

  • @yon2004
    @yon2004 3 ปีที่แล้ว +1

    Can we get a video about how a nonce works? Like do you need to keep a list of all previous numbers used so you don't use it again?

  • @Furiends
    @Furiends 3 ปีที่แล้ว

    Besides "its shuffled around" its really obvious why this actually works. To understand cryptography first is to understand the importance of XOR. If you combine two bits you cant bias either without revealing information and the opposite of XOR is the same as the input. Put another way XOR given a random key and non-random plaintext givens the same distribution as the random key. You cant glean any information without the key. So with just XOR and a random key that is intractable (the key cant be easily brute forced.) You have a robust cipher. The problem is sharing random data is hard. The key needs to be predictable to trusted parties and appear completely random to everyone else.

  • @av2678
    @av2678 2 ปีที่แล้ว +1

    Wow this cipher is real smooth

  • @squishmastah4682
    @squishmastah4682 3 ปีที่แล้ว +5

    @3:48 ...and this concludes Mike's arm exercises for the year... 😂

  • @Jahus
    @Jahus 3 ปีที่แล้ว +3

    Please, do a video to explain BIP-32 deterministic key derivation process. Would be amazing!

  • @LightFykki
    @LightFykki 3 ปีที่แล้ว

    Great video! Was just wondering about this cipher recently and why I was seeing it often in the product description for a few embedded security modules.

  • @INT41O
    @INT41O 3 ปีที่แล้ว +5

    The main advantage over salsa20 is, that it runs very efficiently using SSE (2 of the bit rotates can be replaced by byte shuffles, since multiples of 8 are used):
    void round(m128i &a, m128i &b, m128i &c, m128i &d) {
    m128i R8 = {3, 0, 1, 2, 7, 4, 5, 6, 11, 8, 9, 10, 15, 12, 13, 14};
    m128i R16 = {2, 3, 0, 1, 6, 7, 4, 5, 10, 11, 8, 9, 14, 15, 12, 13};
    m128i e;
    a = paddd(a, b);
    d = pxor(d, a);
    d = pshufb(d, R16); // rol 16
    c = paddd(c, d);
    b = pxor(b, c);
    e = pslld(b); // rol 12
    b = psrld(b); // rol 12
    b = por(b, e); // rol 12
    a = paddd(a, b);
    d = pxor(d, a);
    d = pshufb(d, R8); // rol 8
    c = paddd(c, d);
    b = pxor(b, c);
    e = pslld(b); // rol 7
    b = psrld(b); // rol 7
    b = por(b, e); // rol 7
    }

  • @Produkt_R
    @Produkt_R 3 ปีที่แล้ว +44

    No Mike, we would like to see you dance.

  • @victornoagbodji
    @victornoagbodji 3 ปีที่แล้ว

    😊 😊 🙏
    thanks for sharing these videos. this series is such a delight!

  • @xyz2112zyx
    @xyz2112zyx 3 ปีที่แล้ว +2

    I have a background in Computer Science, but "oh, man", those operation diagrams are difficult to follow when programming. But, anyway, we wait for another episode of Dr. Mike and his outstanding topics about number and computing. Thanks, Computerphile and Dr. Mike!

  • @largenewbragle8138
    @largenewbragle8138 3 ปีที่แล้ว +11

    A Die Hard reference. Noice, smort!

  • @moxi299
    @moxi299 3 ปีที่แล้ว +1

    Could you make a video about "ecs" or "Entity component Systems"? I wonder what the benefits of ecs are in compare to standard computing.
    I heard ecs is using a data oriented Architecture instead of an object oriented.

  • @chexo3
    @chexo3 3 ปีที่แล้ว +4

    This seems like it’d be very easy to implement in digital logic, which might be the point.

  • @dawnstudios7813
    @dawnstudios7813 3 ปีที่แล้ว +3

    "Chacha" in Hindi means "dad's younger brother" ("dad's elder brother" is a different word).
    So when I first read the title, I thought about my uncle.

  • @JustAnotherAlchemist
    @JustAnotherAlchemist ปีที่แล้ว

    I have RFC 8439 compliant Chacha20 written in hand tuned PIC assembler. When run on a 64Mhz (16M C/s) PIC18 it hits the mid to high hundreds of KB/s throughput, almost 1MB/s. So I concur, it's very lightweight.

  • @makatron
    @makatron 3 ปีที่แล้ว +1

    Pound for pound, great explanation

  • @Tospaa
    @Tospaa 3 ปีที่แล้ว

    Thank you Dr Mike Pound, love your videos!

  • @gwahli9620
    @gwahli9620 3 ปีที่แล้ว

    While Rjndael cipher has a 256 bit version, the AES is defined as 128 bit block and key size.

  • @hcblue
    @hcblue 3 ปีที่แล้ว +1

    don't be a coward. we ABSOLUTELY need a video of Dr Pound dancing on the internet. :D

  • @tamrix
    @tamrix 2 ปีที่แล้ว +1

    "and it has a cool name" I'm sold.

  • @korpos8833
    @korpos8833 3 ปีที่แล้ว +2

    The man, the legend ...

  • @suncrafterspielt9479
    @suncrafterspielt9479 3 ปีที่แล้ว +3

    He is back

  • @neumdeneuer1890
    @neumdeneuer1890 3 ปีที่แล้ว

    Nice explanation.
    Suggestion: a video about the general pros and cons of stream and block ciphers.

    • @jkmicha
      @jkmicha 3 ปีที่แล้ว

      Nowadays, people mostly use block ciphers in CTR (or GCM) mode, which is basically the same as stream ciphers. So there's no big difference anymore.

  • @FalcoGer
    @FalcoGer 3 ปีที่แล้ว

    Most processors, even RISC processors have AES instructions, making it very, very fast to execute. It's easy to implement in hardware. Anything else will have a very high computing overhead. AES is literally 16 cpu instructions after loading the key and message into the registers.

  • @kellymoses8566
    @kellymoses8566 8 หลายเดือนก่อน

    You can make a pretty secure encryption algorithm using sha3 and xor.

  • @stromboli183
    @stromboli183 3 ปีที่แล้ว

    What’s the reason for using the 4 constant blocks, and using 2 blocks for both the index (stream position) and nonce?
    Why not just use 4 blocks for the index and nonce each? Considering the 20 rounds of shuffling, it shouldn’t matter that most of the index (position) bits will initially be zero in most cases?

  • @figloalds
    @figloalds 3 ปีที่แล้ว

    I made a system similar to this one but with a 256-long byte array and using each value as a pointer to an index in the array, so that changing the data changes where in the data will be changed next

  • @albertrenshaw4252
    @albertrenshaw4252 3 ปีที่แล้ว +10

    1:36 - why does this sound like he actually did break AES and is about to release the paper and this isn't hypothetical.... ☹️

    • @maxmustsleep
      @maxmustsleep 3 ปีที่แล้ว

      I mean quantum computers are simply ripping through our current encryption algorithms so it's not hard to believe it will be cracked at some point in the future

    • @MisterOA
      @MisterOA 3 ปีที่แล้ว

      I definitely got that feeling too. I guess we'll wait and see.

  • @dembro27
    @dembro27 2 ปีที่แล้ว +1

    Fitting the process on one whiteboard is a real cha-cha-challenge.

  • @franatrturcech8484
    @franatrturcech8484 3 ปีที่แล้ว

    Thank you! Gonna jump in to the editor and try to program this in JavaScript or Python idk

  • @GeorgeBratley
    @GeorgeBratley 3 ปีที่แล้ว +1

    Featuring Dr Mike Pound and the last whiteboard marker in Nottingham

  • @shivam.kumar.the.boy.
    @shivam.kumar.the.boy. 3 ปีที่แล้ว

    Welcome back Mike 😌

  • @wassollderscheiss33
    @wassollderscheiss33 3 ปีที่แล้ว

    Well, I like your Dr. Mike, of course! But you can watch this thing only for entertainment, if you don't go and put it to use afterwards. I know because while watching I remember having watched the bit on AES when it came out and although I completely understood it that time, I don't remember anything of it now. (disclaimer: I own the Schneier book for more then 20 years now)

  • @qm3ster
    @qm3ster 2 ปีที่แล้ว +2

    > *complains the board is vertical aspect*
    > *runs out of hight*

  • @user-iu1xg6jv6e
    @user-iu1xg6jv6e 3 ปีที่แล้ว +1

    13:27 Is there some kind of filter?

  • @Mr.Beauregarde
    @Mr.Beauregarde 3 ปีที่แล้ว

    Close up of face check,
    But where will we find an arrow?
    Brady, rhymes with brilliancy

  • @saeeddessouky1680
    @saeeddessouky1680 3 ปีที่แล้ว

    hey. I know it's out of scope but why do not get someone professional to talk about TDD (testing technique), and advanced topics in embedded systems because I really love your channel. thanks in advance

  • @chexo3
    @chexo3 3 ปีที่แล้ว +2

    It seems to me like this would be very easy to implement in digital logic.

  • @WCL31986
    @WCL31986 3 ปีที่แล้ว +3

    Woo hoo going to Pound Town!!

  • @RealAnonymousse
    @RealAnonymousse 3 ปีที่แล้ว +8

    Imagine having Mike as your university teacher!

  • @allahwetrust9626
    @allahwetrust9626 9 หลายเดือนก่อน

    are u next to the tv because the cypher called shasha ....maaan i know these cypher algos are kinda efficient but since punlic they r backdoors meant to be left or somthing you know the secure thing is a custom cypher

  • @locbuinhien1360
    @locbuinhien1360 3 ปีที่แล้ว

    Will you talk also SVD (singular value decomposition)?

  • @derbyspcollie
    @derbyspcollie 3 ปีที่แล้ว +1

    Welcome back to the best presenter by far.
    Please go back to the printer paper - the whiteboard is useless for viewers.

    • @paulw987
      @paulw987 3 ปีที่แล้ว +1

      Especially with the anemic marker!

  • @shahriyarnasim3757
    @shahriyarnasim3757 3 ปีที่แล้ว

    Welcome back Legend.😘

  • @dedelefoudu88
    @dedelefoudu88 3 ปีที่แล้ว

    why to not use a more random constant like some cypher use a round constant base on Pi

  • @forthrightgambitia1032
    @forthrightgambitia1032 3 ปีที่แล้ว +1

    You should cover Blowfish.

  • @holthuizenoemoet591
    @holthuizenoemoet591 3 ปีที่แล้ว

    Cool, so how does the skipping of blocks work? because with a stream cipher you normally initialize "ksg" once right?

  • @phillips2400
    @phillips2400 3 ปีที่แล้ว +6

    Since you mentioned the paper: do you actually use this paper for printing or is it left over stock from 30 years ago? Cause it looks like the paper I used on my needle printer in the 90‘s :-)

    • @RahulAhire
      @RahulAhire 3 ปีที่แล้ว

      There's also coloured paper available in markets. It's a wood colour dye coated on it

  • @CaiodeAlmeida
    @CaiodeAlmeida 3 ปีที่แล้ว +1

    Read Captcha on the title, came in and ended up staying haha

  • @elsharkio
    @elsharkio 3 ปีที่แล้ว +1

    I like this Pound guy

  • @gabriellecrawford5542
    @gabriellecrawford5542 3 ปีที่แล้ว

    So does ChaCha use perfect forward secrecy?

  • @ranierialthoff7372
    @ranierialthoff7372 3 ปีที่แล้ว +1

    I'll be here the entire day waiting for that paper

  • @yaktd5704
    @yaktd5704 3 ปีที่แล้ว +1

    This guy is Chacha(Father's brother is known as Chacha in Hindi) Computer

  • @rajatpetwal7676
    @rajatpetwal7676 3 ปีที่แล้ว

    Can you make a video about side channel attack on RSA?

  • @honpaul2203
    @honpaul2203 3 ปีที่แล้ว

    this is an awesome video and an awesome comment for the algorithm.

  • @johnchessant3012
    @johnchessant3012 3 ปีที่แล้ว +1

    Yes it's Mike!!

  • @AnotherPointOfView944
    @AnotherPointOfView944 3 ปีที่แล้ว +12

    Smarter than the average bear!

  • @kice
    @kice 3 ปีที่แล้ว

    I am little bit confused about how NONCE works and how to use them in AES or ChaCha in this case. Right now, I used the key as a seed for RNG, thus I could get same output for both side. Or should I set this "seed for NONCE" up during key-exchange process?

    • @franatrturcech8484
      @franatrturcech8484 3 ปีที่แล้ว

      The nonce is not a secret (unlike the 256bit key), just a source of randomness in the process, so that you can use the same 256bit key for more messages. so you randomly generate a nonce, use it during encryption, and send it along with the encrypted data.

    • @softwarelivre2389
      @softwarelivre2389 2 ปีที่แล้ว

      @@franatrturcech8484 the way CTR and GCM modes work seems a bit weird to me. You should be able to reuse the IVs if your message is different if you encrypt the message too, but they only encrypt the iv+counter and then XOR the message, which is a problem.

  • @matshoemolsen4868
    @matshoemolsen4868 3 ปีที่แล้ว

    A video about Dr Mike Pound dancing.... I'll watch that.

  • @RustyTube
    @RustyTube 3 ปีที่แล้ว +2

    Yes, but Cha-Cha almost brought the Umbrella Academy to its knees.

  • @eLBehmo
    @eLBehmo 3 ปีที่แล้ว

    Where do we save the nonce?? It is part of the key input. So we have to know it if we want to decrypt an encrypted stream! Is it saved with the output stream?

    • @franatrturcech8484
      @franatrturcech8484 3 ปีที่แล้ว +2

      i think you would just send it along with the encrypted data, as nonce is generally not a secret (unlike the key).

  • @manfriedschmidt5953
    @manfriedschmidt5953 3 ปีที่แล้ว +2

    Man like Mike!

  • @srmendoza
    @srmendoza 3 ปีที่แล้ว

    So when is salsa video coming out??

  • @djdamagedome
    @djdamagedome 3 ปีที่แล้ว +2

    7:12 Yeah... Nakatomi Plaza...

  • @Ojisan642
    @Ojisan642 3 ปีที่แล้ว +3

    Sometimes when you’re facing a particularly difficult problem, you need to take a step back. And then a step forward. And then a step back. And now you’re chacha’ing.
    (h/t to the movie “Real Genius”)

  • @ivahardy4885
    @ivahardy4885 3 ปีที่แล้ว +10

    I thought that "board" was just a cupboard. Is Dr Mike a secret street artist?

  • @Jone952
    @Jone952 3 ปีที่แล้ว

    Wait. So if you XOR some bytes by a key then XOR those bytes by the same key, you get the original bytes back out? Why did I never realize symmetric encryption is so simple?

    • @absalomdraconis
      @absalomdraconis 3 ปีที่แล้ว +2

      Because the _real_ work is in getting the key.

    • @softwarelivre2389
      @softwarelivre2389 2 ปีที่แล้ว

      Because it is vulnerable to bit flipping, and then you'll need a Message Authentication Code to garantee everything is correct. And even so, repeating your IVs is a problem, so that's why I believe the message should be encrypted too, and not only XORed with the IV + Counter as in CTR and GCM modes.

  • @rahem027
    @rahem027 3 ปีที่แล้ว

    I dont know who coined the bame but ChaCha in hindi means uncle

  • @WilcoVerhoef
    @WilcoVerhoef 3 ปีที่แล้ว +1

    For extra safety you could double-dutch it by rolling some cha cha over your aes

  • @MrRaulMaster
    @MrRaulMaster 3 ปีที่แล้ว

    It would be cool if you had Bernstein in one of your videos!