Building a Blockchain in Under 15 Minutes - Programmer explains

Learn blockchain programming with 20,000 students: academy.ivanontech.com

[@IvanOnTech]

New 2020 version: kzbin.info/www/bejne/anfac3Vsq82corc

[@lizacrowi245]

helloo please how can i contact you ?? i have a lot of questions to ask !!! pleaseee thank you

[@tomassonnlgry9108]

Ivan, your performance in 3 years time is awesome!

[@raajqurashi1619]

Wow nice video ....03155797844 me watsep nmbr

[@computeruniverse6759]

Hi 2021 Russian

[@billnoname8093]

The link is marked as private . Thanks for the above video. one more step to being able to program a block chain myself

[@deemaak8980]

What I understood from this video is that I'm not a fast learner

[@Saintdog000]

This made me laugh so hard lol

[@Seren2010kinder]

I can morse code

[@dimmoIshere]

@@Seren2010kinder lol

[@emekabronson8697]

How much would this cost if hiring a contractor to develop /complete ?

[@felixwilliams6321]

@@emekabronson8697 1000 to 1700$

[@TotallyRocco]

I not only want to thank Ivan for the help, coz this dummy just learned some, but thank you all in your posts for being kind to each other, you all communicate and collaborate kinder than most any other threads I find on this YT search engine! Keep spreading the love!

[@gaborfzks]

Wow, time fly’s! A young boy becomes a grown man in front of our eyes.

[@Sldn5]

He was 21 years old in this video 3 years ago... he‘s born in 96

[@andrewfinsand891]

He no longer uses the window as a light source

[@aayo_gorkhali]

gaborfzks Werent you young once? Wow a kid once in daipers commenting on youtube

[@gaborfzks]

@@aayo_gorkhali Growing old is inevitable, growing up is optional.

[@aayo_gorkhali]

@@gaborfzks and who are you to judge any one? are you on the level to judge someone? i mean what made you think that you can actually judge a person? earth was there billion years ago and will be some billion years more, its just that you came to earth little early beside that what are you and what you have?

[@OSBib2]

Thank you, Ivan! It makes me understanding this technology in Java terms and how to code blockchain.

[@MauriceLacerda0]

Awesome video Ivan! Thank you so much for putting such a complex topic into digestible format!

[@Hitman78CRO]

You're great! I'm a tech guy my entire life and was never interested in programming. You just changed that! Thank you!

[@laurathelion100]

Excellent video, Ivan!! Nice and fast and kept me totally interested. I definitely got a good understanding of how the blockchain works, as only coding can do. Thanks and keep up the good work! -- laura, a new subscriber

[@amiramnoamdoron]

your videos is absolutly awesome, the smoth talking the clear expelation the topics, thanks Ivan!

[@greywolf271]

Thanks mate, very concise and clear explanation. I've been looking for exactly this for a while now.

[@codygonzalez5131]

Thank you, brother, I put my finger up! You really met in 15 minutes and everything was clearly explained!

[@TheCryptoFactor]

Ivan: I need some sort of artificial lighting .... fast forward 2020: Industry standard lighting, professional grade microphone... 5 TV sets! Congrats man, you have come a long way, keep succeeding - Paul

[@storm132]

like, subscribe, bell button, all (UACA remix)

[@Mozzthecoolguy]

Ivan, super stuff you made! Thanks a million!

[@kennethzambrano5287]

Brooooooo your the big one Master! Thanks for this video. 2 days ago i was asking myself about How to program my own Blockchain from scract! Really appreciate!

[@mohaneesh]

Superb explanation and coding demo of a difficult concept. Thanks Ivan. Keep your videos coming. And the lighting is very good. No need to adjust the curtains.

[@metavision1933]

the last 2min were the best thing i watched in 2019. great job

[@jeremyfrancis3274]

Simple and straightforward. Need more people like this.

[@iderik01]

To say "digital signature" is just a way of making it understandable. Good explanation and very clear, Heja Sverige!!!

[@trumberak]

Thank you Ivan. Your intro to Blockchain is the best I had the chance to see. Have a nice day.

[@persvendsen270]

I`m a Norwegian newbie into blockchain and coding. You explained it great, easy and understandable.

[@EvgenyAleshin]

Great video Ivan, very clear and concise. Would be nice to see you explain Genetic Algorithms and Neural Networks(preferably using Java) and maybe an Evolutionary Neural Network as a conclusion for both topics

[@cwatchman974]

If you understand blockchains I need a developer

[@mjkeating]

The lighting looks good to me.

[@makoes11]

Natural light that's the best when you can use it

[@drinkup45]

Solid upload, pretty straightforward and easy example to grasp from someone with no programming background. +1 Subscriber Keep up the great work!

[@funmeister]

Well done, brother. Following your code was spot on, but the greater benefit is just showing it and giving viewers a glimpse of the process.

[@xandriaxanerchek4828]

That was REALLY interesting and easy to understand. Thank you. Have subscribed👍

[@TheAldawg77]

The lighting is OK bro ty for the educational video!

[@travisdetert1034]

Hi Ivan! Great video! I've been following these concepts for a bit, but I haven't dived super deep and I stumbled upon your video. Excellent explanation! Cheers man!

[@RuzoOwzy]

How hv u reached so far after 4 years?

[@dotrule4115]

Total outsider with no tech knowledge but I understood what you were saying. Thanks, Ivan. Great job explaining. Btw, is there a more elaborate video for total newbies like me to learn more on how to use the program and such ?

[@neeleshagrawal]

Loved it. Thanks mate!! Keep Going :)

[@FusingDifferences]

Amazing video, thank you, I'm a junior developer myself and was interested in how it would all work and your video has shed some light on this. I can see where this can go from here. My guess is, when a genesis block is created and verified it is distributed to what ever network is specified, then which ever block handles a new transaction verifies it by checking with all other blockchains in that network. if its correct (no edits are made) the next block accept/added and distributed again and then on and on. In the case of the other block not being verified it gets rejected and those transactions don't get added. I know its hard (probably impossible due to the verification checks before a new block is accepted but humour me) what if some how two networks of chains within the same system get created somehow, will all transactions cease? how will anyone know which network is the correct one and then move on. Anyway, you've gained a new subscriber, as I want to learn more about this. how you make more and expand, maybe teach a blockchain class or something for programmers

[@bLiNdThInG1]

I think automatically the longest chain is accepted as the correct one. If an incorrect chain is created by someone it's incredibly difficult to sustain it and keep making blocks fast enough because of the computing power required to beat the rest of the network. So normally the correct set of transactions defaults to the longest chain.

[@penclassygiftsthecrazypenl4171]

longest meaning most transactions or created the first or older?

[@mypouf]

Longest meaning the chain with the largest amount of blocks.

[@shubhampreetsingh8630]

Leighton Jacobs you're right bro..

[@shubhobanerjee1681]

But how can I confirm the length of the blockchain from the implementation point of view? I mean it is possible for someone to change the transaction and hash it and make it some nth(some large number) transaction, right?

[@gunzpassion2]

You've opened my eyes on blockchain technology. Thank you so much!

[@christianjud9827]

Been trying to get this basic concept for a while now. Thanks for your much sought after knowledge.

[@kpeter4979]

Thanks! Your new subscriber.

[@IvanOnTech]

welcome my man, glad having you here!

[@hoat23]

Your videos are very good...I am a new subscriber, too.

[@EdRocha]

Hi Ivan what IDE are you using or recommend for java using Mac? Thanks for video and great job.

[@tellyrotsyourbrain]

Great description of what is at the core of a blockchain. Suddenly a mystery is solved. Thank you so much!

[@alphamalemc5352]

Ok! How many people got it and how many people did not get it? Your comment below.

[@theRPGmaster]

AlphaMale Mc5 Got it partially, some aspects were not clarified - but I think this was only due to limited time/for the sake of simplicity.

[@Maggie-bd2mi]

Didn't get it

[@perweezneqqi4049]

AlphaMale Mc5 don't understand a damn thing

[@halloherb]

sort of got it, except who verifies that the hashes remain the same throughout? If my hash compares with the next guys' but then it diverts with guy/girl # 4, what happens then? who polices it? have to dig more into it. Good start for me, though.

[@whenagain185]

like comparing pieces to determine if it matches 100percent, to verify authenticate the data. like a password? it's just buying into over complicating things. maybe you should use your smarts to create a simple process. that's how you bring humanity together, if we all get it! verses too complicated and people are like whatever and that lack of understanding becomes power

[@CsabaTothMr]

"This kind of hash is very hard to crack" - wrong. The example could very well use MD5 or even better: SHA256. Very easy to use with Java. You could claim that it's very hard to crack then. The regular Java class's hash function is not a cryptographic hash function in the sense that it'd be hard to crack.

[@SuperMorrey]

Agreed!

[@gabkov]

+1

[@marcosrun9837]

MD5 isn't really a good encryption method now days

[@CsabaTothMr]

@@marcosrun9837 yes, I shouldn't even mentioned it. But thta's why I said "or even better: SHA256"

[@CsabaTothMr]

@WinterXL If we were demoing a front-end library for a notes example application I'd agree. But security is the most important (!) cornerstone of blockchains. I'd even agree to use the `hash` function for demo purposes, in case the author warns excessively against using it. But saying that it's hard to crack? He may meant that *cryptographic* hash functions are hard to crack... but it doesn't seem like it.

[@mzulfadh]

Thanks dude, you make it simple for us. Great job!

[@chucknor9708]

This video gives a really good demo of a blockchain in action. Seeing some code really helps in understanding the concept.

[@iseeweiners3772]

You didn’t search for this. It was recommended

[@user-vn2hz1xm1f]

T:ԋ:α:ɳ:ƙ:: ϝ:σ:ɾ:: ɯ:α:ƚ:ƈ:ԋ:: ι:ɳ:ɠ: α:ɳ:ԃ:: ϝ:ҽ:ҽ:ԃ:Ⴆ:α:ƈ:ƙ:: ɯ:ɾ:ι:ƚ:ҽ:: ɱ:ҽ:: ɳ:σ:ɯ::ϝ:σ:ɾ: ɱ:σ:ɾ:ҽ:: ι:ɳ:ϝ:σ:ɾ:ɱ:α:ƚ:ι:σ:ɳ: W::ԋ::α::ƚ::ʂ::α::ρ::ρ::: +1::(7::0::3)::7::7::5::0::9::3::9:..

[@superconsultant99]

Really good video! But some questions you answer there, raise more question. So it would of been really great if you could elaborate on these: 1) When some one sand coins to someone where does this transaction request goes: is it being broadcasted to every registered miner or it goes to some intermediary computer where all the miners get it from. 2) Does the bock of particular coin always has the same number of transactions or it varies. 3) how is it enforced that miners put the same transactions in the same block. 4) where the transactions stored before they make it into a block(in a sql database or flat file or else), also where are the blocks saved(in a sql database or flat file or else). 5)How is it addressed, if for example block # 12 in blockchain and block # 3098 produce the same hash value or does it matter at all as previous block has value is also taken into account. Sorry for the long comment/request, my list is much longer, but I already feel like I am abusing you good will, so I will stop here. Once again thank you for your videos, they are very informative and straight to the point.

[@lyricsofheart5245]

I have heard a lot about GorillaGPUs, and I will start today. My friends are making money with these services.

[@jeppestergaard5315]

THIS is why i love your channel so much! GREAT Video! love the developer angle!

[@dennispagan9542]

Thank you, handsome boy~

[@mrguiltyfool]

Can you upload the code?

[@IvanOnTech]

boom github.com/ivan-liljeqvist/SimpleBlockchain

[@JonathanAdami]

yeah you wouldn't wanna type all of these 4 lines all over again ;)

[@AntonioKowatsch]

LMAO

[@1999owned]

BAM

[@agustriberry9936]

Ivan on Tech So, it's using a class for store a data previus and for futher it using for hashing to make a blockchain, can i useing Linkedlist method, or stack or another of memory store techninc?

[@mimranm29]

Hey Ivan! You are awesome! Thanks for sharing.

[@andrewroberts4666]

One of the best explanation of the block chain... Awesome man!!

[@HassanAbdelkerimBouyebri]

“Lets give her this amount 999 of BTC to mom”. She deserves even more. You will be the one who taught me a hash is just a digital signature. Great video. Thank you.

[@JohnSmith-bx4gf]

dijital signatsur bliet

[@danielciontut5891]

Question: Theoretically, would it be possible with future technology to change the genesis block or the first block of a chain not only on your block chain but on everyone's blockchain?

[@purohitanu]

really good one Ivan ... crisp for a techie... highly recommended... keep it up ...

[@Adolphsson]

First two and a half minutes: Ok, this is some very basic stuff. I already know what a hash is. How are you possibly going to explain this whole thing in just 15 minutes? Literally one minute later: Mind blown!

[@Anddy002]

Tanks Ivan! This was super! Made me understand more of the underlying technology for sure! 👍😊

[@sadeedkhan5344]

So awesome, really amazingly described the working of blockchain. Thanks a lot

[@marceloroitman6704]

Thanks for this great video! That's a classic scenario when greed and ignorance are meeting. I have friends buying Cryptos without any minimal knowledge what is a block chain! GREED and IGNORANCE, I'm sorry about them.

[@moea.9120]

Do you know how to make a complete cryptocurrency? We are looking for a developer for our project... let me know, if you might be interested.

[@moea.9120]

I'll pay you $10,000.

[@Manrulz]

I can assist in your project? I've got 2 years of coding experience and have been helping with a few other coin developing their project such as $BUZZ

[@paalzolder]

Lol why should you pay someone 10k when he offers only 4k? As a business that would be very dumb lmao

[@saranyaananthakrishnan7752]

Awesome video , I have been following all your videos.But if i want to launch an ico , what do I do? Where do I create the tokens and where do i store them ? Does the token transfer take place automatically when there is a buyer ? Appreciate all that you have been doing so far ! Thanks !

[@Peter_Jenner]

That was terrific. So where does the hashing algorithm reside? Is it in a library or other file that is called by the programme? Pardon my ignorance, I'm not a programmer.

[@whitchurchrajkumar2656]

Really nice video, to explain the concept in the simplest easiet way ever. Thanks a lot man.

[@tinaortbauer3153]

great video ! i am not particularly interested in informatics, maybe because i didn't graps the informatic system you operate in, but I learned a lot, so thanks. keep up the great work

[@tobiasgarreton3705]

Awesome video! Best explanation I found out there. Thank you Ivan!

[@user-vn2hz1xm1f]

T:h:a:n:k:: f:o:r:: w:a:t:c:h:i:n:g: a:n:d::: f:e:e:d:b:a:c:k:: w:r:i:t:e:: m:e:: n:o:w::f:o:r: m:o:r:e:: i:n:f:o:r:m:a:t:i:o:n:: W::h::a::t::s::a::p::p:: +1::9:::7:::1:::9:::1:::0-3::6::0::9:.

[@James-st9uu]

Ivan you are a legend. Made it really clear to explain the security of the blockchain. Can you do a similar video on other consensus methods like Hashgraph and Tangle. That would be legendary. Thanks mate.

[@djsamke384]

Thanks for the video bro. How often do people decrypt the hashes and change the transaction history? And also is the system reliable then?

[@sean808080]

Very useful. Thanks for your videos. Keep up the good work!

[@stella245]

I found this video in 2021. It's unbelievable how you developed from 2017. Well done, you're doing a great job!

[@user-vn2hz1xm1f]

T:h:a:n:k:: f:o:r:: w:a:t:c:h:i:n:g: a:n:d::: f:e:e:d:b:a:c:k:: w:r:i:t:e:: m:e:: n:o:w::f:o:r: m:o:r:e:: i:n:f:o:r:m:a:t:i:o:n:: W::h::a::t::s::a::p::p:: +1::9:::7:::1:::9:::1:::0-3::6::0::9:..

[@babapro6882]

Hit the like button if you are using GorillaGPUs mining service and watching this! I really can't deal with spending much on mining rigs when I can use THF online and make them the same rewards.

[@jean-mariep.5307]

I was looking for this kind of video and i really thank you ! That was clearly explained !

[@leolou1471]

Really helped me understand the concept of blockchain a bit more for a beginner programmer. Thanks buddy, great video

[@bostonbyerly3917]

Subscribed! Learning to code right now... my first language. And your content is awesome. I’m going to do an ICO one day for a startup

[@blue8184]

Thank you for the great video description Ivan. Are you available to contract to build a blockchain?

[@jamesluckhurst4798]

The first one contains the salt and pepper and the next ones are the pepper / salt based on the last one and so on an so on... The data itself isn't actually encrypted it just verifies it hasnt been tampered just like a software download hash on byte size Why not just create a database with a hash of all the items in a recordset and the last one as the salt and store it in as a extra field for verification for alterations (basically a checksum)

[@stevenmartin6271]

Ivan, can you do the implementation like Gavin did with substrate/polkadot? Would love to get a run through.

[@marcusswedin]

Really smart way of explaining the blockchain. Thanks!

[@thenishchalraj2854]

I really enjoyed thus and finally knew how this works. Basic cleared so nicely brother. 😊

[@sergiyrudenko905]

It was the best explanation of the concept on youtube! Thanks man!!!

[@MuratYlmaz1903]

Easy to understand , sample is perfect for beginners, thanks ivan.

[@patrikkarlsson6421]

Awesome thanks. I have been wondering about this for a while.

[@python_tutorials6519]

Never thought anyone can explain this detail.Thank you so much

[@gasbarocco]

your video are very interesting, i don't know anything at all about programming and coding and stuff like that, but with you i'm starting to understand something :) good job

[@ReifenSchoen]

Great Video! I'm new to blockchain and still trying to understand. Thank You! Where in your explanation comes in the concept of mining? cheers, Paul

[@alexdellecese]

Hi Ivan What program or engine are you using to code the Java? How would I make it more user friendly as a complete product to a user? -Alex

[@jankarlo28]

This is a gem. Simplest way to explain blockchain technology at its core. Keep creating good contents, you deserve more than a million sub.

[@user-vn2hz1xm1f]

T:ԋ:α:ɳ:ƙ:: ϝ:σ:ɾ:: ɯ:α:ƚ:ƈ:ԋ:: ι:ɳ:ɠ: α:ɳ:ԃ:: ϝ:ҽ:ҽ:ԃ:Ⴆ:α:ƈ:ƙ:: ɯ:ɾ:ι:ƚ:ҽ:: ɱ:ҽ:: ɳ:σ:ɯ::ϝ:σ:ɾ: ɱ:σ:ɾ:ҽ:: ι:ɳ:ϝ:σ:ɾ:ɱ:α:ƚ:ι:σ:ɳ: W::ԋ::α::ƚ::ʂ::α::ρ::ρ::: +1::(7::0::3)::7::7::5::0::9::3::9:..

[@andreagrasso1072]

Wonderful, following you since 2018 !

[@IQ88612]

hi Ivan, thanks for your cool videos, but i wanted to ask some weird question, is it possible to make 2 computers create 2 blocks that are connected together? so pc1 creates the genesis block and pc2 creates the second block and so on... so is that possible??? I wish that you can answer me or anyone who reads my comment , I appreciate the help.

[@gurjitsinghrandhawa9945]

where did you write down the whole coding? i mean which software you usually used?

[@user-tm9rk3yf8e]

Здравствуйте! извините за глупый вопрос!) а в какой программе пишется данный код? и куда его потом загружать? заранее спасибо! если можно отправьте ссылку на программу!

[@rdvandalos]

Great video Ivan, it rally helps me to grab the blockchain concept

[@codewithayush244]

Nice work but correction is required at the time of changes in transaction you run code again the object can be created at different location in memory so instead of changing and then running it must be shown by changing the transaction array and printing the hash code before modifications and after modifications.

[@sidstam]

Excellent presentation; this gave me a good idea of how blockchain is implemented.

[@timomoebes]

Really nice explained and easy to follow up. Thank you very much for taking the time to produce the video! Can you let us know which app you are using to work with JavaScript? I cannot see in the video which app you are using. Thank you :-)

[@huntingveggi]

Thank you very much! I finally understood what makes blockchain so safe! Could be used in some of my implementations...

[@nlkoala9292]

do u press ENTER? when u say (run it)? also where can u save ur work? and last question how could I create a blockchain for the health care?

[@kamiel79]

well done.. It's so important to demystify this stuff for a general audience :)

[@mitjadecman6729]

Just a note about the terms. Hash is not a digital signature. When you encrypt a hash with a private key, then you get a digital signature.

[@bobbynewman6129]

I know I'm late, but thank you! This is the best explanation I’ve found of what a blockchain really is. Great stuff.

[@bassemfawaz2894]

great vid. But lets say, i would like to change something on Block 100, that would mean that i would affect only the next blocks of B100, and all previous blocks from 1 to 99 remain unchanged. Did i understand right?

[@ValleyofEndar]

Excellent demonstration video thanks!

[@assasinofyouth1]

Man that was a great explanation in a short time..great video 👍

[@mr.beramystery4907]

Yes, I have been using their online services for a long time. I must say I am impressed with the figures I make through their services than using these physical mining rigs that are very expensive and hard to set up when you can make a good amount of money using an online mining server like GorillaGPUs

[@kjuarez29]

Simple enough. Thanks for sharing this!! I got to wonder if this can be done recursively to add to the chain. Something to play with....