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How the Bitcoin protocol actually works

michaelnielsen.org

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Re: How the Bitcoin protocol actually works

#31

Post by fernly »

Here's two dumb questions you might want to answer in a follow-up (and I encourage you to write more articles).

1. If it's a principle that "everybody" has a copy of the block chain, and the block chain records every transaction ever, isn't that going to be a storage problem? How big is one person's copy of the block chain now, and how many petabytes might it grow to be in a few years?

2. The way to spend a fractional coin is to have one input and two outputs, one back to yourself with the unspent change. But doesn't one's wallet begin to be cluttered with lots and lots of little fractional items? Like having a pocketful of small coins... So is there an automated way to every so often, do a many-small-input, one-big-output payment to yourself to consolidate the change?

Re: How the Bitcoin protocol actually works

#32

Post by rallison »

fernly wrote: post #31

Here's two dumb questions you might want to answer in a follow-up (and I encourage you to write more articles). 1. If it's a principle that "everybody" has a copy of the block chain, and the block chain records every transaction ever, isn't that going to be a storage problem? How big is one person's copy of the block chain now, and how many petabytes might it grow to be in a few years? 2. The way to spend a fractiona…

1. This is something that has come up in discussion a fair amount, as the blockchain is already GBs in size and takes a fair amount of time to even sync with peers to download it all. There are a number of proposals for "thin" clients that will hopefully address this:

https://en.bitcoin.it/wiki/Thin_Client_Security

2. I'm not sure what you are asking here. Transactions are almost always fractional as is - you can send as little as 0.00000001BTC at a time. I think I am missing what you are asking.

Re: How the Bitcoin protocol actually works

#33

Post by perone »

fernly wrote: post #31

Here's two dumb questions you might want to answer in a follow-up (and I encourage you to write more articles). 1. If it's a principle that "everybody" has a copy of the block chain, and the block chain records every transaction ever, isn't that going to be a storage problem? How big is one person's copy of the block chain now, and how many petabytes might it grow to be in a few years? 2. The way to spend a fractiona…

Trying to answer: 1. https://en.bitcoin.it/wiki/Scalability#Storage 2. This is actually implemented by the client and is not visible to the user, the bitcoin-qt client creates hidden change addresses that are not shown to the user, so you should see it as a "backend implementation" and not something you'll see in your transaction list.

Re: How the Bitcoin protocol actually works

#34

Post by perone »

maaku wrote: post #20
macrael wrote: post #19

How many transactions end up in a block? How big are blocks?

As many as will fit, and maximum 1MB.

Recently, a new patch is going to enter in the bitcoin-qt client that increases the default size of the block for miners from 50k to 300k to accomodate higher transaction volume.

Re: How the Bitcoin protocol actually works

#35

Post by fernly »

rallison wrote: post #32
fernly wrote: post #31

Here's two dumb questions you might want to answer in a follow-up (and I encourage you to write more articles). 1. If it's a principle that "everybody" has a copy of the block chain, and the block chain records every transaction ever, isn't that going to be a storage problem? How big is one person's copy of the block chain now, and how many petabytes might it grow to be in a few years? 2. The way to spend a fractiona…

1. This is something that has come up in discussion a fair amount, as the blockchain is already GBs in size and takes a fair amount of time to even sync with peers to download it all. There are a number of proposals for "thin" clients that will hopefully address this: https://en.bitcoin.it/wiki/Thin_Client_Security 2. I'm not sure what you are asking here. Transactions are almost always fractional as is - you can sen…

In the article is the example of paying somebody 0.15 of a bitcoin with the input of 0.20 and two outputs, 0.15 to the payee and 0.05 back to oneself. I am picturing having my wallet cluttered with lots of such little fractional bits, the "change" from transactions. How to tidy up? But maybe the answer is, next time I want to pay somebody 0.10 I just give them two my 0.05 "nickel" pieces... Well, I said it was a dumb question...

Re: How the Bitcoin protocol actually works

#36

Post by diminoten »

fernly wrote: post #35
rallison wrote: post #32

Earlier quoted context omitted.

1. This is something that has come up in discussion a fair amount, as the blockchain is already GBs in size and takes a fair amount of time to even sync with peers to download it all. There are a number of proposals for "thin" clients that will hopefully address this: https://en.bitcoin.it/wiki/Thin_Client_Security 2. I'm not sure what you are asking here. Transactions are almost always fractional as is - you can sen…

In the article is the example of paying somebody 0.15 of a bitcoin with the input of 0.20 and two outputs, 0.15 to the payee and 0.05 back to oneself. I am picturing having my wallet cluttered with lots of such little fractional bits, the "change" from transactions. How to tidy up? But maybe the answer is, next time I want to pay somebody 0.10 I just give them two my 0.05 "nickel" pieces... Well, I said it was a dumb…

If you want to, you could create a transaction that lets you spend all of those "loose change" transactions into a bigger transaction.

You have to do this for assurance contracts [0], for example, where the transaction cannot have any change (a transaction back to yourself).

[0] - https://en.bitcoin.it/wiki/Contracts#Example_3:_Assurance_co...

Re: How the Bitcoin protocol actually works

#37

Post by javert »

lsc wrote: post #30
javert wrote: post #29

Earlier quoted context omitted.

What I said isn't a platitude. It is straight to the point.

"a remark or statement, esp. one with a moral content, that has been used too often to be interesting or thoughtful." Your statement /was/ to the point. that doesn't make it not a platitude.

A platitude would be, "Money doesn't buy happiness," or the equivalent. I specifically did not say that.

I don't want to talk about this any further. We have misunderstood one another to the point that this isn't productive.

Re: How the Bitcoin protocol actually works

#39

Post by wmf »

fernly wrote: post #31

Here's two dumb questions you might want to answer in a follow-up (and I encourage you to write more articles). 1. If it's a principle that "everybody" has a copy of the block chain, and the block chain records every transaction ever, isn't that going to be a storage problem? How big is one person's copy of the block chain now, and how many petabytes might it grow to be in a few years? 2. The way to spend a fractiona…

2. Unspent transaction output (UTXO) bloat exists but today it doesn't really cause any problems. Maybe once ultimate blockchain compression is implemented there will be an incentive for people to merge their UTXOs.

Re: How the Bitcoin protocol actually works

#40

Post by adam-f »

In answer to the question:

"Suppose Bitcoin mining software always explored nonces starting with x = 0, then x = 1, x = 2,\ldots. If this is done by all (or even just a substantial fraction) of Bitcoin miners then it creates a vulnerability."

The reward for mining the block includes the miner's account, so each miner is hashing a unique block.

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