Homework on Stale Blocks

Blockchain and Bitcoin 101
#3110

1: When two miners solve a block at the same time the network will have two versions of truth, but sooner or later there will be another miner and that miner will also try to add his block into the blockchain. Depending on which block the miner adds his/her block, the other block will be dropped because the network will always choose the longest chain interms of proof of work.

2: Stale blocks are those blocks that have been in the blockchain at one time but we’re dropped because the nodes got another version of truth that was longer and did not contain those blocks in it.

3: When two miners solve a block at the same time, only one block gets appended into the blockchain and the other block is dropped. The dropped block is called a stale block and that’s how it comes to being.

4: It is important to wait for more than one block to be confirmed when sending or receiving a transaction because the transaction might be contained in a stale block that will surely be dropped.

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#3111
  1. What happens in the bitcoin network when two miners solve a block at the same time?

When there are two miners that solve a block at the same time, at some point another miner will link to one of the two blocks. The network accepts the longer chain that has more difficulty, the most PoW. The other block will be returned to the mempool.

  1. What is a stale block?

Stale blocks or orphaned blocks are blocks that were in the blockchain at one time but then got dropped because there is another version of the blockchain that is longer.

  1. How do stale blocks occur?

Stale blocks occur when miners solve a block at the same time and there are two versions of the chain until one becomes longer making the other chain invalid. The blocks in the invalid chain are known as the stale/orphaned blocks.

  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

The best practice is to wait for 6 confirmations, 6 more blocks after your transaction because there is a possibility that your block can get dropped.

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#3112

  1. A fork in the blockchain occurs.

  2. & 3. The losing fork’s accumulation of verified, yet lagged out transactions due to another blockchain becoming longer and therefore having more proof of work. The lagging blockchain is then ignored and not used, which all transactions must now be put back into the mempool.

  3. The potential of accidental forks in the network is a real plausibility and one cannot be certain if their transaction is in the winning or losing fork. However, once the network advances and the results are in, enough blocks will be added to the blockchain as the transaction would have successfully transpired through a losing fork, re-added to the mempool and attached to a verified block.

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#3113
  1. What happens in the bitcoin network when two miners solve a block at the same time?
  2. What is a stale block?
  3. How do stale blocks occur?
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

Answers:
1/ If two Miners solve a block at the same time the block with the longest chain will be the winner and the other block will be considered as a ‘‘Stale Block’’ or ‘‘Orphaned block’’.
All TX will then go back to the Mempool.

2/ A Stale Block is a block that used to be in the blockchain but was dropped because another chain was longer and produced at the time more blocks , and to be the longest chain. Network will always choose to trust the longest block chain.

3/ A Stale block Occur when Two Miners mine a Valid Block approximately at the same time, Both found a Nonce number below the Target.

4/ It is important to wait more than one block to be confirm due to the fact that when once of the chain get the longest one and accepted as the main chain of the network , ALL the transactions of the losing chain are returning into the mempool until it get picked up by another Miner into the next block.

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#3114

1)Two versions of truth i.e 2 block chain will be created and network will choose the chain with most POW
2) A stale block is a valid block which is dropped out from the chain due to part of a smaller chain and return back to mempool
3)When 2 valid blocks are solved at same time
Stale blocks occur
4)It is important to wait till 6 blocks confirmation which shows that the block is in longest chain

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#3115

  1. What happens in the bitcoin network when two miners solve a block at the same time? They both able to append to the blockchain but whoever the next block chose to appended will get validated and the other block that has not been chosen will be removed. Only one version of truth.

  2. What is a stale block?
    The block that has successfully managed to appended to the blockchain but was not lucky enough to be chosen by the following block for that reason it was removed from the blockchain.

  3. How do stale blocks occur?
    When two blocks successfully solved the cryptographic puzzle.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Because the transactions that you’ve had might be on stale or orphaned block.

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#3116

When two miners solve a block at the same time, the miner who receives confirmation wins and the losing block is dismissed and becomes stale. Preferably six confirmations solidify that a valid block has been added.

A stale block is a block that was once in the chain but has been bumped out and is no longer valid.

A stale block occurs when a competing block wins with confirmations and is the longest block chain.

It is important to wait for more than one block to be confirmed when sending or receiving a transaction because a competing block could win out and render your block stale. A lot of work for nothing.

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#3117

  1. The chain is split into two chains. The longest chain will win and the transactions from the other chain will go back to mempool

  2. A stale block is a valid block that is not accepted by the network

  3. By two miners mining a block at the same time

  4. To ensure your block has been used and not a stale block

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#3118

  1. Both blocks get appended to the same last block on the blockchain and different versions of the updated blockchain propagate through the network.

  2. A stale block is one that has been dropped off the blockchain.

  3. Stale blocks occur when more than one block is mined at the same time and there isn’t enough time for the first one to propagate through the network so two different versions of the blockchain appear. Th network always accepts the longest chain so when one of the two split chains gets longer, the extra blocks on the other one become stale, get dropped and the transactions are returned to the mempool.

  4. In order to ensure that the block is not stale. A transaction is considered confirmed after 6 block confirmations are received.

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#3119

1. What happens in the bitcoin network when two miners solve a block at the same time?

When two miners solve a block at the same time, they will propagate their solved block to the nodes around them, effectively creating two legit versions of the blockchain simultaneously.

2. What is a stale block?

A stale block is a block that has been dropped after being overridden by a better version of the blockchain.

3. How do stale blocks occur?

Stale blocks occur when blocks get dropped from the blockchain as they were initially propagated at the same time as other block(s). They end up as stale blocks when a better version of the blockchain has been accepted by the network via Proof of Work.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

Waiting for more than one block to be confirmed allows for the blockchain to properly synchronize and validate itself by eliminating potential stale blocks.

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#3120

  1. The chain forks into two ends.

  2. A block that was dropped from the chain due to a fork.

  3. They occur when two miners mine a valid block at the same time creating a fork. Once the fork is resolved, the block from the shorter chain is discarded.

  4. Reduces the odds of creating more stale blocks

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#3121

  1. The block which is longer wins and the other block becomes an orphan block.

  2. A stale block is a block that has been dropped due to another block being accepted by the network.

  3. Stale blocks occur when two minors validate a block at the same time due to a global network.

  4. The block can become orphaned so you can wait for six blocks increasing the length so that the block becomes validated.

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#3122

Waiting more confirmations does not reduce the odds of stale blocks occurring. It merely insures your tx is not part of it. :slight_smile:

#3123
  1. What happens in the bitcoin network when two miners solve a block at the same time?

The propagation of the 2 new blocks across the global network means that there are temporarily two versions of the truth. The version of truth known by the miner that achieves the next block will determine which version of truth is retained. Once that block is added to the blockchain, that version of the chain will be the longest one, which all nodes will recognize as the correct chain. The shorter chain is discarded.

  1. What is a stale block?

A stale block is the competing block that is dropped after its chain becomes the shorter.

  1. How do stale blocks occur?

If 2 blocks are mined when convergence of the first block has not completed across the network, the possibility arises that the newer block doesn’t contain the hash of the older block. This means one of the blocks will be rendered stale by the aforementioned ‘longest chain’ preference.

  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

The risk is that you take some costly action based on a completed transaction that ends up in a stale block. Such transactions are returned to the mempool and thus should eventually be added to a valid block, but to reduce risk 6 confirmations (additional blocks) minimum should follow the transaction.

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#3124
  1. What happens in the bitcoin network when two miners solve a block at the same time?

it creates 2 versions of blockchain where 3rd miner decideson which version he will use and by making one of the versions longer the other is removed

  1. What is a stale block?

stale block was once in blockchain but got removed as it was in shorter version of another blockchain

  1. How do stale blocks occur?

they ocur if there are two versions of blockchain from one becomes longer and the other gets removed - stale block was in the removed version of blockchain

  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

we know that blocks are made every 10 minutes and if there are two versions of blockchain at one point eventualy one will get removed we dont want to be removed because of this now incorect blockchain, so thats why 10min is allowed for the whole network to sync and confirms the TX on the blockchain

  • we are waiting for ideally 6 transaction to get confirmations (blocks) that they have been succesfully placed in the correct version of the blockchain
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#3125

1. What happens in the bitcoin network when two miners solve a block at the same time?
The blockchain forks and the longest chain wins. Other block in the shortest chain becomes orphan/stale and returns to the mempool
2. What is a stale block?
A stale block is a block that ended up un the shortest end of a forked chain
3. How do stale blocks occur?
They occur when two miners add two valid blocks at the same time (aprox)
4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
To avoid the creation of stale/orphaned blocks

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#3126

Waiting more confirmations does not prevent stale blocks. It merely ensures your tx is not part of a stale block and gets dropped back into the mempool. :slight_smile:

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#3127
  1. If two miners solve a block at the same time, whoever ends up the shorter chain gets dropped known as a stale or orphaned block.
  2. A stale block is a block that gets dropped from the chain from being in the shortest chain after a fork.
  3. A stale block occurs by being dropped as a result of being in the shorter chain after the fork.
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#3128

ha! :slight_smile: Thank you for clarifying

#3129
  1. There will be 2 competing timelines, 2 competing versions of truth.
  2. A stale block is a block that was once accepted, but it’s not accepted any more.
  3. Stale blocks occurs when 2 miners solve a block at the same time, but then one miner chooses one version and adds an other block, and this version of truth becomes accepted because it’s longer. The other miner’s block becomes stale.
  4. It’s important, to make sure that the latest block is not a stale one.
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