New answers tagged blockchain
2
The problem with this proposal is that it relies on data that is external to the blockchain (namely, data that is in another branch of the chain).
The validity of a block should be a function only of its contents, and the contents of anything the block commits to through hashes. Specifically, that includes all ancestors of the block, as the block header ...
2
According to https://en.bitcoin.it/wiki/Private_key
any 256-bit number from 0x1 to 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4140 is a valid private key.
So if someone generates a private key using the usual random process, and then you generate a private key using a random process there is one chance in 0xFFFF FFFF FFFF ...
0
Is there any way to recover this now seven years old wallet?
No.
This is because you probably ignored any advice to
keep somewhere safe a separate written note of your recovery phrase (seed phrase, backup phrase) or private key.
Make regular backups of important data on your computers (including on your phones)
Practise recovery from those notes and ...
2
From the point of view of an application developer, it is for now much easier to use layer 1 features.
This is due to being able to externalize your burden on the network.
1. Hey nodes, will you do my job?
Blocks are expensive to produce
You don't need to have much DOS concerns in your application if you are only reacting to onchain payments. But what ...
4
the code could have a way to order transactions and if an attacker decides to do the opposite intentionally and decides to spam the network
This is the crux of the issue: how do you achieve this? It isn't a trivial problem to solve in a decentralized network. The more generalized version of this non-trivial problem is called the Byzantine General's Problem, ...
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Since the accepted answer on this question is from 2013, I think this question is ripe for an up-to-date answer :)
DarcyThomas's answer still applies, if one would assume that the island nation is completely cut off from the Bitcoin network: mining would come to a standstill since the island nation's hashrate would likely not be able to find any blocks at ...
1
I have seen people say that you just need the private key and "some software" to recover your bitcoin. What does this actually mean in the real world? Can someone give an example?
What it means is that your funds are secured cryptographically, and not on a server somewhere.
If you lose your private key(s) there's no customer service rep that can ...
1
If the computer that stores the bitcoin is destroyed, how does someone access their bitcoin?
Buy a new computer, download and install almost any wallet program, then either restore a backup of their wallet data file or key in their secret number or key in a phrase of typically 12 or 24 words that is turned into their secret number.
I have seen people say ...
1
When Alice pays Bob, she creates a Bitcoin transaction. Her payment to Bob is defined in an output of the transaction. This output is encumbered with a cryptographic challenge tied to Bob's public key. You can think of this as the funds getting stored in a lockbox addressed to Bob. When Alice's transaction gets confirmed, it gets recorded in the Bitcoin ...
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You have to know the private key. That's it, that's always it. If the private key was never dumped, that is recorded in some way, or the wallet.dat file not copied somewhere else (the wallet file contains the private keys), it's over. The coins are gone.
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Just for fun I made a program to list all record low hashes starting from block 1 ...
Max block count: 677124
Block 1 : 00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048
Block 2 : 000000006a625f06636b8bb6ac7b960a8d03705d1ace08b1a19da3fdcc99ddbd
Block 4 : 000000004ebadb55ee9096c9a2f8880e09da59c0d68b1c228da88e48844a1485
Block ...
1
If there are two competing blocks at the same height (which happens rather infrequently), each node will only consider one of the two the best chaintip. The other block is not part of their best chain, so it is irrelevant what transactions it included. Therefore, the same transaction can be in multiple competing blocks at the same time. If the transaction ...
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When blocks become stale, transactions in them are returned to the pool.
Transactions in the pool are available for inclusion in a subsequent block on the winning fork.
1
What I am now wondering however, is if I sync the entire blockchain (300GB+) and at some point want to --enable-wallet, will I be able to do so without any incompatibility issues?
Yes, there's no issue with this. You will need to rebuild with --enable-wallet (or use the release binaries which bundle BDB), but this will have no impact at all on the ...
1
This is precisely what federated byzantine agreement algorithms like that used by XRP and Avalanche do. But this is a such a huge change that you can't really consider the algorithm to be proof-of-work anymore.
What happens is that a block is not accepted when it is mined but some subsequent process that can only happen once the block is public is required. ...
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A node verifying that a transaction is performed looks at the block chain... but perhaps more explicitly, it looks at "block chains." There's no actual requirement that a node only look at just a single block chain when deciding whether a transaction is valid or not.
They can then assign some level of trust as to whether the transaction occurred, ...
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I understand that bitcoin wallet is nothing but transaction record performed on block chain.
A bitcoin wallet stores keypairs, and allows the use to interact with the network by sending/receiving bitcoin transactions.
How are transaction details updated in decentralised block chain?
A 'full node' can be run by a user that wants to independently verify the ...
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I understand that bitcoin wallet is nothing but transaction record performed on block chain.
Bitcoin wallet is mainly used for secure key management. But wallets also show transaction history associated with the addresses which are derived from keys or added as watch-only in the wallet.
How are transaction details updated in decentralised block chain?
I ...
3
A coinbase transaction is allowed to have as many outputs as the miner wishes so long as the total amount in those outputs does not exceed the block subsidy + transaction fees for that block.
Thus a miner could create a coinbase transaction which has more than one output which pays to himself and someone else. It doesn't matter who the recipients of the ...
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The design of the blockchain is such that such a scenario is not possible. By definition, the genesis block does not have an ancestor block. While it has a field for the previous block hash, this field is set to all 0's to indicate it is null and has no value set. This means that there are no blocks that come before the genesis block.
Additionally the ...
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User A send a transaction to user B. Those transactions are bundled together into a merkle tree. User A and B can both use the transaction plus the merkle root, plus the merkle path to prove the merkle root in the block header is correct.
Let me rephrase your question to ensure we are on the same page:
Alice pays Bob. When Alice submits her transaction to ...
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where these unconfirmed transactions are stored before being included in block
Mempool
Each node (wallet, miner, etc) stores them in a local collection called the "mempool". The name implies these are typically kept in memory (RAM) but the developers of each wallet software can decide whether to also store the data onto non-volatile storage such ...
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