Introduction to Blockchain - II (History)

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[@utsavseth6573]

Beautifully Explained.

[@ayanparmar3476]

Very nice n clear explanation sir...👍👍👍

[@mahendratomar1505]

Thank you sir for such explanation !!. Sir , but how can anyone look and cross verify new transaction by looking into previous blocks transactions as previous blocks contains message digest using some cryptographically secured function and these are one way function.

[@diptanshumalviya7547]

Thank you sir for such nice explanation !!. Sir , what if the miners stop the mining ? or what if the miner couldn't find the nearly hash value ? Due to increasing in the difficulty of puzzle then it hard to find the puzzle or more electricity is need for the mining .

[@siddharthteli1113]

Miner get incentive if they win the race to find the correct hash and propogate to all other nodes/miners. But because no. of Bitcoins that can be mined is limited around 21 million so miners are not solely dependent on new Bitcoin but also charge user for each transaction . Secondly , Difficulty of hash is such that time taken for every new block is around 10 minutes .As you know hardware are getting more Powerful due to which miner can compensate difficulty with better hardware keeping new block time around 10 minutes or so .In early days of Bitcoin miner used normal Cpu for mining ,then started using Gpu ,then they took multiple gpu to calculate hash and today they are using Application specific integrated circuit for mining .This difficulty in mining is only to make miners bear cost to get some reward .If calculating hash was simple then many miners would try to gain unfair benefits by giving fake transaction etc.

[@pravinkolhe82]

Excellent lecture... Thank you Sir

[@asdomain4503]

I dont have the knowledge of cryptography or computer security can i take this course?

[@muralimvg]

Do each of them know the balance of each other person? For example, everyone knows A has Rs. 100 at one point in time and using that they can also know what A has at any other point in time. Similarly, does everyone know what B, J and E have at some point in time?

[@siddharthteli1113]

Currently We can know balance of any user on bitcoin blockchain ,But we still don't know them in real world so there identity is anonymous.In future we might see implementation of zero knowledge proof (only possible in etherum not in Bitcoin) where sharing our exact balance is not necessary .

[@ashishtarun7584]

Doubt: @2:50, here assumed hash function which is H(x)=x % n, is not following the second requirement of cryptographically secured function, i.e. if x1= 36, x2= 32 and n =4, for two distinct X1 and X2, H(x) = 0. Where am I missing?

[@amitpriyankar5577]

H(x)=x%n is not a cryptograhically secure hash function. Prof. was actually trying to give an example of simple hash function. If you wish,you can read about SHA-256(a secure hash function).

[@RahulMadhavan]

@@amitpriyankar5577 by this definition Sha would not be cryptographically secure either. Proof: calculate Sha256(x) where x = [0,2^256]. There will be atleast 1 collision in output of Sha256. and therefore above property not satisfied.

[@kartikagrawal1321]

At 7:16, the professor incorrectly describes the value C subscript x as change value whereas it is clearly mentioned that it is the client id.

[@rakeshkunchanapalli8438]

Anyway, after a few seconds, he corrected it. Go, have a look.

[@vasudevanmk7110]

This technology seems too complicated. Why should anyone else bother about my transaction to another or why should I be bothered about transactions between two parties that I do not know? And what about energy costs involved in prorogation g to all in the network. How does one track Illegal or criminal transactions like drug trafficking, terrorism funding or any other funding of illegal activities (including tax evasion). Also I do not subscribe to the view that centralized control is always bad for the reasons cited above. and about transactions when there is a power outage and other network issues?

[@bhaveshkrishna]

That's the whole point of the technology. Decentralization is the key to maintain privacy and anonymity of the users and their transactions. So, wherever a bright spot like this occurs, people figure out a way to misuse it, and a dark spot arises. This is common in all technologies.

[@jebinabraham]

Mrs Vasundevan M K , The terminology that you meant about others is just to help how the concept works. The others that you mentioned are basically different systems that cross verify the transaction , and no the energy cost will not exceed the one which a centralised system takes

[@jackeychan486]

Because when a miner validates a transaction between two persons , the miner receives some bitcoin as a reward for validating the transaction. That's why miners mine blocks for getting some reward. As of now the current reward for mining a block is 12.5 bitcoins.

[@RahulMadhavan]

Technology doesn't take political sides sir. whats good for government (currency creator/backer) is bad for those against it and vice versa

[@AakashVarma95]

I would like you to use some common sense and watch the full video and then post your comments. Most of the questions you've asked are already answered in the course. Nowhere in the video is mentioned that the centralized approach is always bad.. And one more thing, crime is never a drawback of the technology, but of greed and human mentality.