Lesson 1: Blockchain Basics- Question about the inner workings of key/user authentification on blockchains.

[FrancoRodriguez99]

Hi, sorry for my bad English, its not my mother tongue, I will try to explain myself the best I can, please tell me if something is badly explained or incorrectly "executed"

First, let me take you through what I think is the process of generating and login in a blockchain "account" is, and correct me if I am wrongly interpreting some part of it:

2 concepts before the process:
-The "12 words" is your public key before being hashed into a string.
-the public key is a hashed version of the 12 words, and thus its strongly associated whit the 12 words, you can get to the public key whit the 12 words, but you can't get to the 12 words whit the public key.
-The private key is a hashed version of the 12 words, but only you know about it, not the nodes that compose a blockchain.

For example, if I generate a new account on metamask:
-My computer asks metamask for 12 words at random
-My computer then proceeds to apply some math to the 12 words thus hashing those 12 words into a public key and a private key
-Then My computer goes to the blockchain and identifies itself whit this public key. It doesn't identify itself whit the private key, because in the blockchain everything is public so it wouldn't make sense to show it in public.
-Next time I log in, My computer makes the math to the 12 words I feed it, and comes whit the same public key to identify itself in the blockchain

Here is when my problem comes, if the hash of my 12 words is occurring on my private computer, what guarantees have the blockchain that I indeed did the correct math and the public key hasn't been altered previously to being sent to them?, otherwise I could check the blockchain for any "X" public key, and sent it as it was mine, like saying that I make the hash of 12 words and the final result is this X public key. I am not sure if I am explaining myself correctly?, I am not saying that I "decrypt" the public key, I know this is not possible I am saying that I don't need to decrypt anything to start whit, I could just send it as it is.I assume the private key plays a role in all of this, but if it's private how come the blockchain can check its veracity and remain anonymous?

[alymurtazamemon]

@FrancoRodriguez99 sorry man! I am not able to understand it. Could you please clarify? Are you asking how does public/private keys works behind the scene? or Are you asking about How Metamask gives you 12 words mnemonics, sign transactions, and how public/private key works in it?

[FrancoRodriguez99]

@FrancoRodriguez99 sorry man! I am not able to understand it. Could you please clarify? Are you asking how does public/private keys works behind the scene? or Are you asking about How Metamask gives you 12 words mnemonics, sign transactions, and how public/private key works in it?

I am asking about how public/private keys works behind the scene, I just used metamask as an example.
If I understood correctly, everything in a blockchain is public, meaning everyone has access to all the information on it, so I am having problem understanding how it manages to authenticate public key owners. I get that it hashes these 12 words into a string but, this process of hashing happens on my end, not on the blockchain end, correct? So I can lie and just don't use the 12 words, and give the public key (hashed string) directly to the blockchain, saying "this is the result of my 12 words once hashed" since the blockchain doesn't check how I hashed my 12 words it just checks what my final result is.

The only possible explanation I can think of is that private keys are stored in the blockchain but are somehow completely hidden. Yet this makes no logical sense.

[alymurtazamemon]

@FrancoRodriguez99 See the public key is created with our private key with the algorithm called Elliptic Curve. It is a one-way process means we cannot create the private key back with a public key just like if I give you two prime numbers and ask you their result, it will be very easy for you to tell me that but if I give you a big prime number and ask you their factors that we take your lot of times. The same thing is behind our public/private key.

Now comes to the point, how does blockchain verify that the public key we are giving is our key and we have signed that transaction?

So the answer is also available in the video, but I am going to explain it here. Behind the scene it creates a transaction id with our private key and data (data could be anything). That transaction id could be easily verified with our public key because the public key is created through the private key so the same process applies behind.

Now here I cannot exactly explain everything just try to give you as mush as information.

More you can see more about this on Blockchain Demo Website at the top you will find different things to navigate and get knowledge.

[FrancoRodriguez99]

Yes, it's my fault, now that I rewatched that part of the video, I see that they did explain how they do signatures, it just doesn't really explain the math behind it, so I got a little bit confused maybe It was too much information for me all, I should take a break more often while watching the video.
Thank you for your replay ❤, and sorry if I make you lose some time😅

[alymurtazamemon]

@FrancoRodriguez99 Great! now one thing more marks the discussions as answers (if it answered your query) so others can skip these. Have a good day!