A simple bitcoin Q/A. Learn new and interesting stuff about bitcoin.

[pugman]

Hey everyone,
Bill gator and I decided to start up Q/A contest wherein users can answer the questions we ask about bitcoin. Fair discussions are appreciated. This is only because we want to encourage users to learn more about bitcoin,and encourage them to make quality posts subsequently helping them to receive merits and rank up.
Suggestions appreciated.
How to participate in the contest:

1) Me or Bill gator will ask questions related to bitcoin.
2) Users shall answer the question and they may research and answer if they want.
3) The first correct answer will be counted and that user may receive merit based on how their answer is.
4) The post quality shall be reviewed and if you're a quality poster you may even receive more merits.

NOTE: If either one of us run out of merits,the thread shall be locked temporarily.

Rules:

1. No spamming/posting off-topic replies,otherwise your posts shall be deleted.
2. Users may not enroll with alts,anyone found with using alts,their posts will be deleted and even if the answers are correct,it shall become invalid.
3. Don't pm me or bill gator begging for merits.
4. Wrong answers and repetitive answers shall be deleted. Any means to farm merit shall not be tolerated.
5. If you spam too much you shall be put on ignore and all your posts will be deleted.Not reading the OP and blatantly posting something will get your post deleted.
6. No Bitcoincash shills.
7. If you have any questions that you want us to ask,feel free to PM us.
8. This shall only be related to bitcoin since this is a Bitcoin Forum.
9. If a user answers a question correct or is granted merits in another way from this thread then he will not attempt the next question.
10. No editing your posts after giving your initial answer. Making edits will disqualify your answer.
11.Plagiarizing or copy pasting content from various sources is NOT allowed. Rephrasing such content is also not allowed.

NOTE: I'll take 24-48 hours to update the thread,so don't worry. All users who gave correct answers would get merited soon.

Let's hop right into it then.

[pugman]

Question #1: What is bitcoin’s Mempool? What does it do, what is held there and where is it’s physical location on the network?
Answer:

Code:

The bitcoin mempool is where unconfirmed transactions are stored.
It's a set of all the transactions that have been broadcast but have not yet been added to a block by a miner.
Every node has its own transaction relay policy so there is no definite mempool, but different mempools for different nodes.

Winner:- Xynerise and hugeblackQuestion #2: What is a legacy address? What is segwit address? What is the difference between these two addresses?
Answer:

Code:

Legacy means that you will be using addresses of the form 1... 
Segwit means that you will be using addresses of the form 3... or bc1... (one is for P2SH nested segwit and the other is for native segwit). 
Note that 3... addresses are for P2SH addresses in general and are not just for segwit.
bc1... addresses are for segwit specifically but not all wallets support it yet.*

*Credit: achow101
Source: Legacy vs Segwit wallets. Whats the difference ?
Winner:- Eddie13
Question #3:
When a node receives a block, what does it check for to verify the validity of transactions within it?
What are these checked against?
Answer:

Code:

It checks the signatures of the transaction against previous blocks.

Winner:- Fazlurkhan.kzQuestion #4:
Does Bitcoin have an adaquete solution to the Byzantine Generals problem?
Why not or what is it?
Answer:

Code:

Yes, Bitcoin does have a solution and it is called the proof-of-work algorithm.
So to alter "the message" (a block of transactions in our case) as in the classic Byzantine Generals problem and to make it look authentic by guessing a new nonce, one would need to use more Hash Power than the entire network.
Since the current Hash Rate is around 23 million TH/s, to achieve that they would need to buy 1.5 million of Antminer S9.

Winner:- BetwrongQuestion #5:
Did Satoshi write the Bitcoin Whitepaper or write the code for Bitcoin first?
Why did he choose the one he did to do first?
Answer:

Code:

I actually did this kind of backwards. I had to 
write all the code before I could convince myself that I could solve every 
problem, then I wrote the paper. I think I will be able to release the code 
sooner than I could write a detailed spec. [i]-Satoshi[/i]

Winner:- buwaytressQuestion #6:
In Satoshi's old e-mails they imply that handling as many transactions as Visa should not be a problem.
What does this imply about the development of Bitcoin?
Specifically, what is one parameter that would need to be changed and to what value to accommodate such heavy transaction flow?
Answer:

Code:

Satoshi implies that handling the amount of transactions that Visa processes should not be a problem in time because it was expected that computing power would keep pace with network and transaction growth.
There were concerns with blocksize limits at the time because the bigger they got the more power that would be required with both upload steams (to broadcast to the network) and computing power (to process the transactions). 
The blocklimit was set so that mining operations could not out-power single person operations.

Satoshi's emails re transaction processing imply that higher block limits were anticipated and were an expected development of bitcoin.
This is controversial as a number of people see off chain scaling as a better method instead of increasing block size. 
At 150,000,000 transactions a day that makes 1,041,667 per block (given it can be mined in 10m), and with a transcation size of around 1kb it would need to be just over 1gb.
My understanding is that upload/download speeds should be able to keep pace with this size.

Winner: Wheelige
Question #7:
What is the Difference Between a Blockchain and a Database?
Answer:

Code:

A database is online, but it is kept there by a server computer, so it is centralized by definition.
If I have a database, I control it and I can manipulate it as I see fit. It can be hacked or changed by others.
A blockchain is decentralized, and it is on hundreds or thousands of computers, based on the popularity of the blockchain.
Some, such as bitcoin blockchain is very popular due to the high price, and some others are not so. 
Blockchain is an immutable public ledger and it cannot be hacked, modified, stolen or manipulated. 
If you own 51 percent of the blockchain though, then it could be a problem as they can all pool and do something nasty with that.

Winner: ridertiger
Question #8:
How exactly does a 51% attack work?

Answer:

Code:

If I had 51%, I could mine a chain of blocks in which I transfer all my coins to my personal wallet. 
I'd mine this chain about 10 long, but not tell the rest of the network. 
At the same time, I convert all my coins to dollars on the exchange and withdraw them. This happens on the normal blockchain.

After my withdrawal has gone through. the normal blockchain is about 9 long, while my blockchain is 10 long. 
I announce all my blocks to the network, and lo and behold, the network confirms I am right.

But dollars can't be reverted! So the exchange takes a loss.

Instead of the exchange, I could do this with buying anything for bitcoins. 
If this happens a few times, it will probably kill bitcoin, or at least hurt the trust in the system severely.*

*Credit: BTCurious
Source: How exactly would a 51% attack work?
Winner:bitmover
Question #9:
A bitcoin transaction with 6 confirmations is usually considered to be secure. Why is it so?
Answer:

Code:

With one confirmation you are vulnerable to the 51% attack. There could also be a miner with a lot of hashing power who could get a couple blocks in a row, so three confirmations removes most of them.

With six confirmations it is essentially mathematically impossible for an attacker with less than 51% of all mining capacity to get six blocks in a row. and still surpass the longest block chain. With 51% or a lot more than 51% the attacker can get six confirmations by creating a parallel blockchain in which only transactions approved by the attacker get included in blocks.

Therefore 6 confirmations are needed to prevent the attack from attacker.

Winner: nalinpuri
Question #10:
What are bitcoin days destroyed?
Answer:

Code:

Bitcoin days destroyed is another way to measure bitcoin trading volume, in a more significant way.

This idea was created because 1 bitcoin could be sent thousand times a day, to create a false high volume.

The idea behind Bitcoin days destroyed is to consider in the trading volume equation the number of days each bitcoin has not moved from that address.

So if you have 1 bitcoin that has not moved in the last 100 days, when it move to another address it would have the same weight in the volume as 100 bitcoin that were transferred yesterday.

This equation would give a more precise value for bitcoin volume and economic activity as it cannot be manipulated by whales.

Winner: bitmover
Question #11:
What does double spend mean?
Answer:

Code:

Double spend is to spend the same coins in 2 different transactions. It's mostly attempted when the 1st transaction doesn't have any confirmations yet, because it becomes much harder to successfully do a double spend after each confirmation.
Double spend is usually attempted when someone makes a transaction by mistake, when a transaction gets stuck because of a low fee, or of course for fraud.
There are several ways to attempt a double spend, what I know of them:
Including a higher fee in the 2nd transaction (the one you want to get it confirmed faster), asking a miner to include your transaction in the next block, these two methods work for unconfirmed transactions.
Double spend can also happen in 51% attacks or similar attacks where the attacker has high hash power. In this case the 1st transaction could have a couple of confirmations and still get reversed. Though this kind of double spend is not worth it unless the amount of transaction is so high.

Winner: Oulay

[pugman]

Alright here is the first question.
Since QuestionAuthority motivated us to create this thread, here is the first question guided by him. Question : What is bitcoin’s Mempool? What does it do, what is held there and where is it’s physical location on the network? May the best answer win, remember it is first come first serve.

[hugeblack]

Alright here is the first question.
Since QuestionAuthority motivated us to create this thread, here is the first question guided by him. Question : What is bitcoin’s Mempool? What does it do, what is held there and where is it’s physical location on the network? May the best answer win, remember it is first come first serve.

Memory Pool is a place when Bitcoin transaction being inside After it passes node verification until a miner picks it up in the next block "higher fee go first and lower gets long time [unconfirmed transactions]". it’s a node holding awaiting transaction.

[Xynerise]

Alright here is the first question.
Since QuestionAuthority motivated us to create this thread, here is the first question guided by him. Question : What is bitcoin’s Mempool? What does it do, what is held there and where is it’s physical location on the network? May the best answer win, remember it is first come first serve.

The bitcoin mempool is where unconfirmed transactions are stored.
It's a set of all the transactions that have been broadcast but have not yet been added to a block by a miner.

Every node has its own transaction relay policy so there is no definite mempool, but different mempools for different nodes.

[pugman]

Memory Pool is a place when Bitcoin transaction being inside After it passes node verification until a miner picks it up in the next block "higher fee go first and lower gets long time [unconfirmed transactions]". it’s a node holding awaiting transaction.

Looks like you have some idea at least on what Mempool is and your post quality ain't that bad. You have made some edits and this is the first and last warning for any body, the OP has been updated and editing posts would result in disqualification of the answer.

The bitcoin mempool is where unconfirmed transactions are stored.
It's a set of all the transactions that have been broadcast but have not yet been added to a block by a miner.

Every node has its own transaction relay policy so there is no definite mempool, but different mempools for different nodes.

Good, very good. This is what I expect members to post. Keep up the good work bud. Keep posting good quality posts and you shall never be short of merits. Both of you have been awarded a merit each due to good post quality.

[pugman]

Question #2: What is a legacy address? What is segwit address? What is the difference between these two addresses? This question may seem too easy but yet most of the users don't know the answer to it. May the best reply win. Do note that posting random stuff  won't help you win. Your grammar must be legible and must make sense. Good luck.

[bill gator]

Sorry I am late, but I just wanted to verify that I will also be handing out merits, picking winners, helping pugman dig through the thread in anyway that I can help. We will be formulating questions together, selecting answers and we will be taking suggestions together.

We thought this up in QuestionAuthority's merit upgrade thread, so shout out to them and QA also gave us our first question. Pugman and I discussed this a little bit after that through PM and thought this would be a solid service/thread/discussion.

We're all trying to learn more about Bitcoin, so if you can suggest a question that will make pugman or I think we may give you merit for that as well, or even may include it as one of our questions (of course, you wouldn't be allowed to answer that one and we better not find anyone giving out answers to their own questions!). Anyways, I won't ramble on too much, have at it, hope we all learn a lot, get merits to the people that deserve them and enjoy ourselves while doing it.

P.S. I have to catch up on my sMerit review thread, so my Merit might be a bit scarce for a bit, but all will be rewarded that deserve it and have patience!

[BTCforJoe]

Great idea, but wouldn't this fit better in Beginners & Help? Either way, can you guys make sure to update either the top post or second post with the questions and answers that are posted throughout this topic? It will be much easier to track that way, and when this topic has multiple pages, newbies won't have to go through pages and pages of Q/A. Just my $0.02! Great job!

[eddie13]

Question #2: What is a legacy address? What is segwit address? What is the difference between these two addresses?

I'm not a coder but I'll take a crack at it..

Typically from what I see a legacy addy starts with a 1 and a segwit addy starts with a 3.. Not that this is the end all be all..
As far as I understand, segwit vs legacy transactions use a different code to wright transactions so the data that must be saved in the blockchain to confirm these segwit transactions is more compressed or just smaller than the amount of data you have to save in the blockchain for a legacy transaction to confirm the same/similar transaction.. 

You save on miner fees paid in this way because fees are based on how much data you have to write to the blockchain, or space taken up in a block..
Space is very limited so the less space you take up with your TX the less you have to pay and the more TXs will fit per block in total..
This makes fees paid per TX cheaper and more room for more TXs per block therefore higher throughput capacity total for all of Bitcoin.. Though we haven't scene a very big change because the space savings aren't drastic and hasn't yet been thoroughly adopted by users (including myself)..

I haven't really been sending around a lot of BTC lately due to craziness and the places I use are all still using legacy addys so to be honest I have not used segwit yet..
When I have the option to choose my fees paid I use a somewhat low fee as compared to the current going rate and supplement them with the accelerators available..

This question may seem too easy but yet most of the users don't know the answer to it.

You are right but it is quite technical, you can only get a layman's explanation from me

[bill gator]

~snip~

I would have liked to know why/how the data was able to be compressed or for there to be less data. You are correct though! I encourage you to read a little bit more into it, so you know exactly what is different about Segregated Witness and the old way of doing things. Unless I'm mistaken, it requires less verification checks to confirm transactions with equal precision. I've given you a merit for this. This means do not participate in the next question, give someone else a chance.


I'm going to run my questions a little bit differently, in the hopes that we can bring even more variance in how things go in here; offer more users a chance at the merit through variance.

You can choose to answer at least one of my questions; but if you answer multiple questions you will still be considered for merit even if one of your questions was already answered (as to not punish you for working/researching longer). Sometimes there will be a mandatory question and then an additional two-questions for you to choose one to answer for a total of two answers. For now, just choose Question A or B to answer (feel free to answer both).


Question A)

When a node receives a block, what does it check for to verify the validity of transactions within it?
What are these checked against?


Question B)

Does Bitcoin have an adaquete solution to the Byzantine Generals problem?
Why not or what is it?

[FFrankie]

How do I properly use oclvanitygen, I keep getting these errors


https://postimg.org/image/tvqyvjw4z/


https://postimg.org/image/lq8wxcxlf/

[pugman]

I shall update and reply to every person here :
Update 1:

Snip

I am sorry but you have failed to read the OP and you have broke 2 rules :

5. If you spam too much you shall be put on ignore and all your posts will be deleted.Not reading the OP and blatantly posting something will get your post deleted.
9. If a user answers a question correct or is granted merits in another way from this thread then he will not attempt the next question.

Your post is thus disqualified and shall be deleted.Update 2:

Great idea, but wouldn't this fit better in Beginners & Help? Either way, can you guys make sure to update either the top post or second post with the questions and answers that are posted throughout this topic? It will be much easier to track that way, and when this topic has multiple pages, newbies won't have to go through pages and pages of Q/A. Just my $0.02! Great job!

Thanks for your feedback Joe. I have kept the first post as reserved only to add questions and answers. I would let you know this rather be in services board than in beginners and help, I don't expect much users to participate there. Feel free to join the contest.

I'm not a coder but I'll take a crack at it..

Typically from what I see a legacy addy starts with a 1 and a segwit addy starts with a 3.. Not that this is the end all be all..
As far as I understand, segwit vs legacy transactions use a different code to wright transactions so the data that must be saved in the blockchain to confirm these segwit transactions is more compressed or just smaller than the amount of data you have to save in the blockchain for a legacy transaction to confirm the same/similar transaction.. 

You save on miner fees paid in this way because fees are based on how much data you have to write to the blockchain, or space taken up in a block..
Space is very limited so the less space you take up with your TX the less you have to pay and the more TXs will fit per block in total..
This makes fees paid per TX cheaper and more room for more TXs per block therefore higher throughput capacity total for all of Bitcoin.. Though we haven't scene a very big change because the space savings aren't drastic and hasn't yet been thoroughly adopted by users (including myself)..

I haven't really been sending around a lot of BTC lately due to craziness and the places I use are all still using legacy addys so to be honest I have not used segwit yet..
When I have the option to choose my fees paid I use a somewhat low fee as compared to the current going rate and supplement them with the accelerators available..

This question may seem too easy but yet most of the users don't know the answer to it.

You are right but it is quite technical, you can only get a layman's explanation from me

Eddie, segwit addresses are of two types. One is bech32(starting with bc1) and the other is P2SH(starting with 3). Note that not all addresses starting with 3 are segwit. Multisig address also start with 3 if I'm not mistaken. So please make some edits and change the answer so that I can quote your answer, do answer bill gator's question too. But otherwise you seem to know what the concept is. Update 3:

How do I properly use oclvanitygen, I keep getting these errors
-Snip-

Hey, you can check blankcode's video here, pretty helpful.
https://m.youtube.com/watch?v=570voL9fPp0

That doesn't show how to correct the error
and I should be able to use the gen without internet. so I shouldnt have to use that website
so I got rid of the error by adding the calc address to my C directory
now I get this error
https://postimg.org/image/vq3tdd3qr/

Did you check with the syntax? Do clarify your code with that of here: https://bitcointalk.org/index.php?topic=25804.msg321135#msg321135
Also check this link out: https://legacysecuritygroup.com/index.php/projects/recent/12-software/35-oclvanitygen-compiling-and-use
Github code: https://github.com/samr7/vanitygen
If issue of yours is yet not solved,try asking the technical experts here: https://bitcointalk.org/index.php?board=6.0I think you have mistaken the purpose of the thread. Sure you can ask questions but this is more of a question/answer  to encourage users to learn with the working/functioning of bitcoin. Sorry for any inconvenience caused. Do participate in answering our questions.Update 4:

This is a great initiative!

I'm going to monitor this thread on a daily basis because I find it very interesting to read.

Please do not lock this thread on account of running out of sMerits. Since I have 100+ of them left I would be happy to give my merits to those who you find worthy.
I'm not sure I know how to do it the right way (I mean making people know that they were merited by you actually) but I think you guys can figure it out.
Keep up the great work!

Sure you can handout the merits to users who answer the questions correctly. We'll just announce that if we run out of merits,some one else is free to merit the users. Thanks for your feedback.

Since my proposal was ignored I will try my luck in answering the question because I need merits too.

Sorry I had a couple of really busy and hectic days. You were not ignored.

When a node receives a block, it checks all the previous transactions that tally with the wallet that the sender or the transaction request creator used to send bitcon by means of the reference that each one has as inputs.
The network node has a special record of unspent transactions to speed up the process of checking.

Congratulations.

killyou72 is hilarious for just asking their question, but I can see how that could easily be confusing.

Nevermind.

[FFrankie]

That doesn't show how to correct the error

and I should be able to use the gen without internet. so I shouldnt have to use that website

so I got rid of the error by adding the calc address to my C directory

now I get this error

https://postimg.org/image/vq3tdd3qr/

[Betwrong]

This is a great initiative!

I'm going to monitor this thread on a daily basis because I find it very interesting to read.

Please do not lock this thread on account of running out of sMerits. Since I have 100+ of them left I would be happy to give my merits to those who you find worthy.

I'm not sure I know how to do it the right way (I mean making people know that they were merited by you actually) but I think you guys can figure it out.

Keep up the great work!

[bill gator]

You can choose to answer at least one of my questions; but if you answer multiple questions you will still be considered for merit even if one of your questions was already answered (as to not punish you for working/researching longer). Sometimes there will be a mandatory question and then an additional two-questions for you to choose one to answer for a total of two answers. For now, just choose Question A or B to answer (feel free to answer both).


Question A)

When a node receives a block, what does it check for to verify the validity of transactions within it?
What are these checked against?


Question B)

Does Bitcoin have an adaquete solution to the Byzantine Generals problem?
Why not or what is it?

Question A.
What to check is a stuck transaction / unconfirmed transaction.

Not the answer I was looking for and I'm pretty sure this is not correct. This would be an "outcome" of what is performed, I suppose.  My question(s) still remain unanswered to my satisfaction; feel free to give them a try anyone!

killyou72 is hilarious for just asking their question, but I can see how that could easily be confusing.

[Fazlurkhan.kz]

Question A)

When a node receives a block, what does it check for to verify the validity of transactions within it?
What are these checked against?

When a node receives a block, it checks all the previous transactions that tally with the wallet that the sender or the transaction request creator used to send bitcon by means of the reference that each one has as inputs.
The network node has a special record of unspent transactions to speed up the process of checking.

[bill gator]

I had to read your answer like 15-times, because I just couldn't grasp the wording for some reason. Must've just been reading it wrong, or something. After running it through my head a bunch of times, I've realized that you're correct just using different language than I was expecting. I was mostly looking for something along the lines of "It checks the signatures of the transaction against previous blocks". Sounds like you understand though, so I'll give it to you.


What this means, since I'm running my questions differently is that the next question is simply going to be the other unanswered question.

Question B)

Does Bitcoin have an adaquete solution to the Byzantine Generals problem?
Why not or what is it?

Hint : Don't over complicate  your answer

[Betwrong]

Since my proposal was ignored I will try my luck in answering the question because I need merits too.

Question B)

Does Bitcoin have an adaquete solution to the Byzantine Generals problem?
Why not or what is it?

Yes, Bitcoin does have a solution and it is called the proof-of-work algorithm. So to alter "the message" (a block of transactions in our case) as in the classic Byzantine Generals problem and to make it look authentic by guessing a new nonce, one would need to use more Hash Power than the entire network. Since the current Hash Rate is around 23 million TH/s, to achieve that they would need to buy 1.5 million of Antminer S9.


Btw my proposal remains in force in case you'll find it helpful.

[bill gator]

Yes, Bitcoin does have a solution and it is called the proof-of-work algorithm. So to alter "the message" (a block of transactions in our case) as in the classic Byzantine Generals problem and to make it look authentic by guessing a new nonce, one would need to use more Hash Power than the entire network. Since the current Hash Rate is around 23 million TH/s, to achieve that they would need to buy 1.5 million of Antminer S9.


Btw my proposal remains in force in case you'll find it helpful.

I did not mean to ignore your proposal, but yes that would be excellent. Pugman replies to posts above (https://bitcointalk.org/index.php?topic=2968050.msg30525496#msg30525496), they even responded to you. I will run it by pugman, since it is their thread, but it should not be a problem for us to simply send you a PM when somebody needs a merit or I could keep a little list of people that need their Post # merited. This would help us keep this running without any concern, I appreciate it and accept.

That being said, yes your answer is also correct so I've given you a merit. This means do not attempt to answer the next question.



Question :

Did Satoshi write the Bitcoin Whitepaper or write the code for Bitcoin first?
Why did he choose the one he did to do first?