All Questions
30,221
questions
216
votes
22
answers
95k
views
What is a good way to concisely explain Bitcoin?
Often I'm asked to explain Bitcoin to someone and occasionally I come up with something stellar that really nails it, but most times it's a rambling incoherent mess.
What I would like to see is a ...
- 7,573
204
votes
9
answers
116k
views
What exactly is Mining?
I have heard that mining is for people with ready hardware and blah blah blah... But what exactly is it? Does it operate like real mining? I mean, people talk about it like you are physically mining.
- 2,151
191
votes
2
answers
60k
views
How do Bitcoin clients find each other?
What protocols or algorithms are Bitcoin clients using in order to find their peers? I learnt that BitTorrent clients may rely on central computers called trackers. Do Bitcoin clients need any kind of ...
- 2,751
183
votes
6
answers
233k
views
What are "bitcoin days destroyed"?
The concept of bitcoin days destroyed has been proposed as a measure of bitcoin volume. However, I don't think the bitcoin wiki really explains the idea very well.
What is the purpose or advantage of ...
- 2,465
164
votes
11
answers
390k
views
Why is my transaction not getting confirmed and what can I do about it?
I sent a transaction
without (or with an exceptionally small) transaction fee
using extremely small or unconfirmed inputs
while the stars were not standing right.
For whatever reason, I have been ...
- 1,929
163
votes
6
answers
289k
views
What are bitcoin miners really solving?
As with mining, what are the bitcoin miners really solving? I read they are solving hashes, but what does that really mean. Can we see what they are solving? Can someone give an example of what a ...
- 10.9k
158
votes
6
answers
253k
views
What is a 'Satoshi'?
I am aware that Satoshi Nakamoto is the author of the paper that originated Bitcoin and the creator of the original bitcoin client. However, I often hear the term Satoshi as if it was a monetary unit.
...
- 11.5k
149
votes
8
answers
55k
views
What can an attacker with 51% of hash power do?
Suppose organization X has 51% of the hash power for a period of 1 week. In this week, what exactly can and can't X do?
- 26.5k
140
votes
11
answers
80k
views
Is it possible to brute force bitcoin address creation in order to steal money?
Bitcoin users frequently generate new addresses for each transaction they make, which greatly increases the number of bitcoin addresses being used to receive money.
Would it be possible (and ...
- 11.5k
132
votes
10
answers
46k
views
How much will transaction fees eventually be?
Some people keep evangelizing that Bitcoin transaction fees are much lower than in PayPal or with credit cards.
However, once nearly all 21 million bitcoins have been mined, the network will still ...
- 3,507
130
votes
7
answers
51k
views
How do you obtain bitcoins?
This is a question many people ask when they're introduced to Bitcoin.
Bitcoin sounds interesting, but if I want to use this system I will need to get some coins, otherwise, there's no way I can ...
- 1,620
122
votes
5
answers
23k
views
Why is 6 the number of confirms that is considered secure?
Why is 6 is the number of confirmations that is considered secure? I haven't found any mathematical explanation or otherwise that explains why it is 6 and not 5 or 7. Is there a historical reason for ...
- 5,481
116
votes
9
answers
335k
views
How much Bitcoin will I mine right now with hardware X?
Say I have a given piece of hardware (CPU/GPU). Where can I find out how much Bitcoin will I mine per day?
- 26.5k
113
votes
13
answers
13k
views
Is there a way to set up proof-of-work systems so they would be even more useful?
One of the arguments made against Bitcoin's design choices is that it wastes resources authenticating transactions. In particular, finding small hashes is completely useless for the world.
Are there ...
- 2,016
111
votes
4
answers
82k
views
How does merged mining work?
How does the implementation of merged mining affect the global hash rate of alt chains?
Does one solution fit all? Does one solution fit some? Does the rate of "solutions that will fit" decrease ...
- 3,865
99
votes
17
answers
222k
views
How can I buy Bitcoin via a Credit Card or Paypal?
I want to buy some bitcoins. Ideally, I would like to buy them on the MtGox exchange (because the consensus seems to be that this is the most reputable exchange), however I have found the system for ...
- 1,629
99
votes
11
answers
109k
views
Why was 21 million picked as the number of bitcoins to be created?
Why did Satoshi pick 21 million as the number of bitcoins to be created? What is the significance of that number?
- 5,481
94
votes
15
answers
23k
views
Does hoarding really hurt Bitcoin?
Some people believe that hoarding hurts the Bitcoin economy.
But are they really right?
As long as corresponding goods vendors and services will be here to stay and reinforce people's faith in Bitcoin,...
- 3,507
93
votes
9
answers
189k
views
Why don't people buy at one exchange and sell at another?
Bitcoinity.org shows that for the past 30 days, bitstamp's price is high at 101.00, low at 77.00, and current price is 98.04. On contrast, mtgox's price for the past 30 days is high at 115.00, low at ...
- 2,105
84
votes
3
answers
37k
views
How to redeem a basic Tx?
Given a raw, standard Tx (wiki):
01000000
01
26c07ece0bce7cda0ccd14d99e205f118cde27e83dd75da7b141fe487b5528fb
00000000
8b
...
- 43k
80
votes
1
answer
14k
views
If someone wanted to pretend to be Satoshi by posting a fake signature to defraud people how could they?
If a random fraudster wanted to post a bunch of mysterious ECDSA signatures that the public would believe came from Bitcoin's creator, in order to disrupt the Bitcoin market, extract money from people,...
- 7,676
80
votes
7
answers
90k
views
Can I download the whole block chain from somewhere?
Every time I turn on the Bitcoin client it takes days to catch up with the block chain.
Are there alternatives to getting it trickling through the peer-to-peer network? Can I just download it ...
- 4,751
79
votes
6
answers
19k
views
How can I accept bitcoins on my website?
I have an online store and would like to begin accepting bitcoins. How can I go about doing this?
- 14.4k
78
votes
3
answers
58k
views
What does the curve used in Bitcoin, secp256k1, look like?
I'm reading up on ECC curves and on many of them I see an illustration that looks like this
What does the comparable curve in Bitcoin look like, or are all curves generally the same?
- 12.6k
76
votes
3
answers
44k
views
How is difficulty calculated?
Can anyone explain me in the plain English how difficulty is calculated. I have a very approximate understanding that it is calculated based on the amount of hash power in all the bitcoin community ...
- 3,330
74
votes
2
answers
36k
views
What is an SPV client?
I've seen SPV client mentioned in several places.
What exactly is a SPV client? How is it different from a standard client?
- 3,279
73
votes
4
answers
36k
views
What is a compressed Bitcoin key?
The standard Bitcoin client in version 0.6 apparently introduces compressed keys.
What are they? Are there any drawbacks to using them? Any incompatibilities with older software? Reductions in ...
- 4,751
70
votes
11
answers
11k
views
Will Bitcoin suffer from a mining Tragedy of the Commons when mining fees drop to zero?
One issue that I haven't seen clearly addressed is the possible Tragedy of the Commons in Bitcoin's future (see this answer). 40 years into the future, the only significant direct benefit for honest ...
- 26.5k
69
votes
2
answers
95k
views
Can someone explain how the Bitcoin Blockchain works?
I'm trying to figure out how the blockchain works and how to read it via blockchain.info website. Is there a laymen way of explaining how the block chain works and how to read the blockchain to trace ...
- 10.9k
69
votes
5
answers
74k
views
What happens if your bitcoin client generates an address identical to another person's?
Here's a what-if scenario:
Person A has a Bitcoin address with 25BTC.
Person B opens up their Bitcoin client:
which may or may not have the complete blockchain (the latter would
mean no copies of ...
- 1,109
68
votes
7
answers
162k
views
How many bitcoins will there eventually be?
Since bitcoins are being regularly rewarded to miners, will the number of bitcoins continue to grow indefinitely, or will there be a maximum total number of bitcoins in existence? And if there is ...
- 14.4k
67
votes
9
answers
93k
views
Where do bitcoins come from and what gives them their value?
Where do bitcoins come from? From the WeUseCoins.com video it appears they are just being produced by "miners" and sold to people. So who backs Bitcoin or gives it its value?
- 14.4k
66
votes
5
answers
28k
views
What is a soft fork? What is a hard fork? What are their differences?
When people talk about possible changes to how Bitcoin works they sometimes say a particular change can be implemented as a soft fork. What does that mean? How does this compare to a hard fork?
- 8,419
66
votes
3
answers
82k
views
How to calculate transaction size before sending (Legacy Non-Segwit - P2PKH/P2SH)
I know that I pay the transaction fee per kB, so how can I calculate how large the transaction will be before I send it via the RPC api. I run a site using bitcoins, and I cannot let the user's ...
- 761
66
votes
9
answers
35k
views
How anonymous are Bitcoin transactions?
I read some sources that say Bitcoin transactions are anonymous, some that say they are semi-anonymous, and some that say they are not anonymous at all. In what ways are the transactions anonymous ...
- 3,364
64
votes
4
answers
41k
views
Explanation of what an OP_RETURN transaction looks like
How is OP_RETURN used and why was it introduced in the first place?
- 2,376
64
votes
6
answers
35k
views
What is meant by Bitcoin dust?
I've seen the term "dust" used to describe small transactions that might be considered as spam by the Bitcoin network. Is there is a generally accepted definition of this term?
- 3,302
64
votes
3
answers
73k
views
In the ASIC-age, is it worth starting mining Bitcoin at home?
I have recently learned about Bitcoin and would like to get rich quickly into mining.
I have control of a
laptop
library full of ancient computers
powerful gaming PC
cluster of GPUs
an old ASIC, I ...
- 71.6k
63
votes
3
answers
20k
views
How does the Lightning network work in simple terms?
Could you please describe how the Lightning network is supposed to work?
How does it scale better than pure blockchain transactions?
What are the advantages and disadvantages of Lightning Network ...
- 71.6k
62
votes
3
answers
21k
views
Will there be 21 million bitcoins eventually?
Every x blocks the mining reward is halved. Will the reward be halved forever such that we never quite reach 21 million bitcoins, or will we reach 21 million bitcoins at some point and will the reward ...
- 873
62
votes
6
answers
67k
views
What is the Merkle root?
The Bitcoin wiki Vocabulary article explains why the Merkle root exists:
Every transaction has a hash associated with it. In a block, all of
the transaction hashes in the block are themselves ...
- 11.5k
61
votes
6
answers
26k
views
What is relation between scriptSig and scriptPubKey?
Scenario: A is sending 1 BTC to B.
scriptSig appears in the Input Script.
scriptSig = <sig> <pubKey>
Here, public key is the Public Key of the sender, A. (this is the public key ...
- 1,033
60
votes
4
answers
32k
views
What keeps the average block time at 10 minutes?
I've been told "the network" sets the difficulty level such that there will be one new block mined every ten minutes.
I imagine the rich would instead prefer to keep difficulty as high as possible to ...
- 2,030
60
votes
3
answers
14k
views
Should I leave the Bitcoin client open?
Some people recommended that I leave my Bitcoin client open because it helps the network.
Apart from the security implications, why should I do this? I thought that miners were the ones responsible ...
- 11.5k
59
votes
3
answers
47k
views
What are bitcoin "confirmations"?
When I receive bitcoins I see a certain number of "confirmations" in the client. What do these mean? Why do most sites make me wait for 6 "confirmations" before a purchase will go through?
- 5,402
58
votes
4
answers
998k
views
What is the difference between kH/s, MH/s, and GH/s?
I started mining on a friend's computer and it shows 300 kH/s. But when I research other peoples' hash rates I usually see MH/s. Are these speeds the same as kilobytes and megabytes?
Also, when I say ...
- 867
58
votes
8
answers
40k
views
What effects would a scalable Quantum Computer have on Bitcoin?
A scalable quantum computer is a quantum computer that is easy to extend - adding more (q)bits of memory is not a fundamentally hard problem, and will happen. Or, alternatively, that it follows Moore'...
- 26.5k
57
votes
10
answers
9k
views
What methods could a government use to shutdown Bitcoin?
Let's say that a government decided to shut down the Bitcoin network. What options would they have to achieve this? Would they need to convince other governments? All governments?
Let's set as a ...
- 3,454
57
votes
7
answers
54k
views
Can bitcoins be counterfeited?
Traditional currencies have anti-counterfeiting features designed to make them hard to copy, but despite this attempt counterfeit money is a real threat. Since bitcoins are digital, it's trivial to ...
- 14.4k
57
votes
4
answers
7k
views
Have any cryptography experts vetted the bitcoin source code?
Theoretically, bitcoin's open source nature makes it more resistant to bugs and exploits. However, due to the specialized nature of the code, even many programmers don't fully understand the ...
- 5,402