Most Popular

1500 questions
40
votes
2 answers

How does Ripple solve the double-spend problem?

How does the Ripple system solve the double-spend problem? Does it also use some block-chain-like entity that officially dictates which transactions are confirmed and which are not, or does it use some other clever mechanism?
ThePiachu
  • 43,091
  • 25
  • 139
  • 348
40
votes
5 answers

Why are hashes in the bitcoin protocol typically computed twice (double computed)?

According to the wiki specification of the bitcoin protocol, hashes are typically "computed twice". For example: hello 2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824 (first round of…
40
votes
4 answers

What are orphaned and stale blocks?

If I understand it right, a stale block is a block for which an earlier confirmation has been found and was accepted by majority of people. This block is considered invalid and is later never used. But what is a orphaned block. How is it created?…
Salvador Dali
  • 3,360
  • 7
  • 31
  • 50
40
votes
5 answers

How do I accept bitcoin payments at a real world store?

From what I understand, there are some requirements for using bitcoins at a physical store: Both the store owner and the client must have Internet access The client must have a cellphone or a laptop to issue the payment The seller must have a way…
nmat
  • 11,509
  • 14
  • 50
  • 78
40
votes
3 answers

What is a stealth address?

Stealth addresses are mentioned in the context of privacy of bitcoin transactions. What are they and how would they work? Can they provide 100% anonymity?
Emre K.
  • 3,188
  • 2
  • 21
  • 46
39
votes
11 answers

How to check if the block chain is up to date using bitcoind or json-rpc?

I read the full api method list and did not seem to find one. I suppose there is no command specifically for that purpose, so what is the general way of doing this? I would consider checking the time stamp of the last generated block, but the…
Steven Roose
  • 11,841
  • 8
  • 45
  • 73
39
votes
5 answers

What is a deterministic wallet?

It sounds as if it's a process that enables a wallet to be rebuilt from a passphrase, or from several fragments scattered about. Could someone provide a detailed technical explanation?
Gary
  • 7,593
  • 3
  • 33
  • 59
39
votes
4 answers

How to fork Bitcoin and build own cryptocurrency

Is there any step-by-step tutorial about how to build own cryptocurrency based on Bitcoin code?
Michal
  • 609
  • 1
  • 7
  • 9
39
votes
4 answers

What are checkpoints?

I often read that checkpoints protect the network from a 51% attack because an attacker cannot reverse transactions made before the last checkpoint. How exactly does this checkpoint mechanism work? And who creates the checkpoints?
nmat
  • 11,509
  • 14
  • 50
  • 78
39
votes
2 answers

What are Green Addresses?

What are Green Addresses? Is it true that they can solve the "confirmation delay" problem, and how does that work? Are there any drawbacks?
Thilo
  • 4,759
  • 5
  • 26
  • 37
38
votes
3 answers

Who runs www.bitcoin.org?

The original client that can be downloaded from www.bitcoin.org is often referred to as the "official client". Similarly many regard www.bitcoin.org as the "official homepage" of the project. So, who runs it? Is it the core developers? Some Bitcoin…
D.H.
  • 5,307
  • 3
  • 32
  • 45
38
votes
2 answers

What is the coinbase?

I searched the bitcoin wiki and found references to coinbase, but no clear cut explanation of what exactly it is. I know that miners can tag their coinbases (that is how some sites tell who mined a block).
Andrew Burns
  • 681
  • 1
  • 7
  • 6
38
votes
2 answers

What is TxIn's sequence?

I'm currently trying to generate the genesis block with my code and I've stumbled upon the TxIn sequence field that is not explained in the Protocol Specification wiki page, nor does it seem to appear in the block explorer. What is the way the value…
ThePiachu
  • 43,091
  • 25
  • 139
  • 348
37
votes
10 answers

How is it possible to launder bitcoins?

Some services, such as bitcoinlaundry.com, claim that they can launder your bitcoins. Since all bitcoin transactions are publicly logged, how is this done? Wouldn't it be possible to trace back the transactions and find out the initial address?
nmat
  • 11,509
  • 14
  • 50
  • 78
37
votes
2 answers

What is Gas Limit in Ethereum?

What is the function of Gas Limit parameter in Ethereum? Is it involved in mining or something else?