What is Hashing on the Blockchain?

What is Hashing on the Blockchain?
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Cryptographic hashing is a key feature in the security and efficiency of blockchains. If you've ever wondered how so much data can be stored securely on every node in the network, hashing is a big part of the answer! We'll cover all the basics you need to know in this video!
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Cryptographic hash functions
A cryptographic hash function is a special class of hash functions which has various properties making it ideal for cryptography. There are certain properties that a cryptographic hash function needs to have in order to be considered secure. Let’s run through them one by one.
Property 1: Deterministic
This means that no matter how many times you parse through a particular input through a hash function you will always get the same result. This is critical because if you get different hashes every single time it will be impossible to keep track of the input.
Property 2: Quick Computation
The hash function should be capable of returning the hash of an input quickly. If the process isn’t fast enough then the system simply won’t be efficient.
Property 3: Pre-Image Resistance
What pre-image resistance states is that given H(A) it is infeasible to determine A, where A is the input and H(A) is the output hash. Notice the use of the word “infeasible” instead of “impossible”. We already know that it is not impossible to determine the original input from its hash value. Let’s take an example.
Suppose you are rolling a dice and the output is the hash of the number that comes up from the dice. How will you be able to determine what the original number was? It’s simple all that you have to do is to find out the hashes of all numbers from 1-6 and compare. Since hash functions are deterministic, the hash of a particular input will always be the same, so you can simply compare the hashes and find out the original input.
But this only works when the given amount of data is very less. What happens when you have a huge amount of data? Suppose you are dealing with a 128-bit hash. The only method that you have to find the original input is by using the “brute-force method”. Brute-force method basically means that you have to pick up a random input, hash it and then compare the output with the target hash and repeat until you find a match.

[@arhabersham]

Great animation to explain such a central concept. Thank you!

[@destamakonnen8204]

Thank you for simplifying this into a teachable concept. Looking forward to more

[@DarioPulcinelli]

Really nice video, short, clear and go straight to the point !

[@djrt]

Awesome vid, thanks and that music is groovy, I dig it!

[@nikhilgowda9750]

The concept was explained very well Thank you!!

[@MotherCoin]

Most clear concept explanation !

[@beselamudemissieofficial1090]

Thanks !!!! short and precise!!!

[@thomasbaird01]

Great explanation. Thank you.

[@v.r.rosete1838]

Thanks for sharing it!!

[@stephensargeant4992]

Great explanation. Learned a tonne of good information here

[@lofigeniustm2216]

Awesome and subscribed!

[@RupinRaj-gd6ex]

Excellent video... Please remove or lower the background music next time, we just want to hear you :)

[@dizzyrocket2000]

At 3:54 I don't think a change in block #3 will "change" the data in block #2. I think it just creates a discrepancy in the chain where the previous hash on block #3 no longer matches the hash on block #2 thus flagging it as erroneous. Please correct me if I'm wrong as I'm still trying to learn myself. Thanks

[@the_billionaire_way]

That's the part im trying to understand too!!!

[@aemde]

That's right, it's all about the matching

[@henriklarsen8193]

If anyone knows a good guide / video to THAT particular question, I'm interested, too!

[@josephegbobawaye3858]

You’re correct… a change in one block cannot create an update in another block… because all other nodes already has a copy of the original block so they fish it out and change it.

[@Journeyjunkee]

Ima watch that 10 times

[@jolo35]

why

[@tanaykamath1415]

anything which causes the hash of the block to get changed affects its subsequent blocks not the previous ones, else a great video!!

[@ChituOkoli]

Great explanation of hashing… but not very clear explanation of how it fits into blockchain. Which is block 1, 2, 3 in the picture?

[@cdflyboy]

Thanks for simplifying the concept. Would be nice great if you could slow down a bit to let it gel in us noobs 😉

[@Helloknight]

0.75 speed

[@shreyaspuri]

Nice ... you should be a Professor!!! :)

[@jamiebury1807]

this applies to our 24 words aswell i assume when entering them into cold storage devices, is there anything you have on this and how it stores it safely and discards the info but still remembers that its been made

[@daylimater4159]

Great , Get me more videos like that with animation its pretty cool.

[@BlockGeeks]

We're glad you enjoyed it! We have lots of animated videos on our channel that you should definitely check out! :)

[@fash252]

Thank you from Ivan student

[@janweibel2894]

I understand the mechanisms and all that but can anyone explain what the pre-picture resistance (point 3) is for? I am writing a graduation thesis and do not understand what the benefit is since the transactions are available to anyone anyways and you can't really change the input after all without getting a different output resulting in a not accepted block. If the information in the input should be kept secure I would understand but I don't see where this ocurrs. Thanks in advance!

[@yousafyousaf4305]

If i have a block number thats transection is not done how can i know what will be it’s hash?? I mean if we are in block 179927 and we have it’s hash and how can i know tha hash of coming block?? Like 179946?

[@parthsarathidixit5648]

What is the use of hash if we can't retrieve the original data from them???

[@Kig_Ama]

What if there is a technology highly fast like say quantum technology, wouldn't it be possible to crack the SHA-256 encryption by using the brute force method in a much shorter time?

[@briangutierrez7404]

I was thinking the same thing. It would have to be some kind of AI system since there are many captcha puzzles nowadays. I want to know the answer to this too.

[@Kig_Ama]

@@briangutierrez7404 I guess no one knows for sure, only time will tell, but my personal trust level into Bitcoin is quite low. I would rather pick the original instead of the copycat and buy gold.

[@mariank7744]

This question occurred to me also. Would love to know the answer. Best wishes from Marian in UK.

[@deb62615]

What the *****. Please tell me the reason why it matters if the next blocks use the previous hash to decide their hash. So what if it's not the same as before? Why does that matter?

[@GULLAPUDILIKITHBCE]

if the previous block hash is changed then the present hash also changes

[@Mksindustrial]

tienes un video con subtitulos en español?

[@KittySYT]

Everyday I'm hashing... 🌚

[@Hiiiiiiiiii12345]

Ummm 🧐 ooook. Backs up slowly

[@jolo35]

?

[@Laxmisaagar1]

thanks! if you are 'smart' like i am :P, you might find it helpful to reduce the speed to 0.75 or 0.5 and watch/listen LOL. at regular speed, it just flew 100 ft over my head LOL

[@jolo35]

LOL

[@markuspfeifenberger9341]

Number 2 is false. Because it makes Bruteforce attacks easier

[@spudhead169]

God damn it, why is there no video on this platform that explains the exact process step-by-step. They're all vague generalizations grrrrrr.

[@Doinitwell007]

I have a headache

[@kerron_]

Trap door

[@jolo35]

drunk?

[@kynnon3490]

Safex blockchain > Bitcoin blockchain

[@user-jl5gj4mv1z]

It was not that good