>> It is by design for Blockchain, because we want the mining
of each block to be computational mounting.
So that the transaction cannot be easily modified.
>> What if I had information that only a central clearing group would know?
So that I could make the mining easy but only if you knew a secret code.
>> Right.
>> That you could do fast, right?
>> Yes.
>> But you'd have to have a secret code that only a few people knew.
That won't work with BitCoin.
For a government issue of a registry of deeds for land.
>> Exactly.
>> Okay, so Blockchain is more than BitCoin,
it could be different than BitCoin, we can use it in many different ways.
BitCoin is simply one way of using Blockchain for cryptocurrency.
>> Right, it's just one special case of it.
>> Okay, one special case.
But all of these cases have hash functions.
>> Yes.
>> And that's essentially encryption and action.
>> Mm-hm.
>> How does that work what's this hash?
>> So hash function in short terms it means that we take the input
off any lens but gives the output alpha fixed lens.
It is a one way function, which means that it is easy to go one way to the other but
hard to go the other directions.
We can take the modular function as an example.
So, for example what 2010 mod 36 will give us 30,
which we can calculate easily but given the result of 30 There
will be unlimited possibilities that congrute to 30 more 36.
That's what we meant by.
>> And if I make a small change to even a tiny bit of data?
>> It's going to look entirely different.
>> It's a totally new hash?
>> Totally new.
>> So it's clearly wrong.
You changed it.
Even a tiny bit, even a penny change, it's all wrong.
>> Yes, and the entire notes on this network will detect this change.
>> And if I change something in history, every block thereafter is invalid?
>> Right.
>> That's a problem, so it breaks the whole chain.
So I can't do that.
>> Right. >> But it's easy to compute.
>> Mm-hm. >> We could just do that on our PC.
We can compute the hash.
>> With a blink of time.
>> But it's hard to find the right one.
>> Right.
>> Okay, all right, so it's a complicated function.
So you've got an example here of a hash function.
How does that work?
>> So if you hash the input of a letter, a,
this long string is what we are going to get as the hash function output.
>> I would like to enter that into my phone.
>> Right.
>> So how do I deal with the long harsh like that?
>> With long harsh like this one,
we dont need to remeber the whole thing- >> Good.
>> As customers, we can only remember our original password or original code.
>> Okay. >> Letter A.
>> Or we can also use a QR code to be able to be recognized by the computer and
interface with a lot of data really easily with your phone.