Homework on Stale Blocks

Blockchain and Bitcoin 101
#3010

  • What happens in the bitcoin network when two miners solve a block at the same time?
    The chain splits. The one with the more difficult transactions will be added to the chain first and the other will become orphaned.

  • What is a stale block?
    Validated block that gets dropped from chain because there are two or more versions of truth being mined at the same time.

  • How do stale blocks occur?
    When another competing block is added in the chain

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

To make certain that your block is truly added to the blockchain.

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#3011
  • What happens in the bitcoin network when two miners solve a block at the same time?

-The blocks all have compete to become the largest in the blockchain, the next block a miner picks will become the main blockchain making the other block a stale block.

  • What is a stale block?

-This is a dropped block that was returned to the mempool.

  • How do stale blocks occur?

-Stale blocks occur when two blockchains are built simultaneously and one of those blockchains does not get used.

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

-To ensure that your tx is valid and its included in blockchain and not in a stale block.

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#3012
  1. If two miners solve a block at the same time then there is a temporary situation where two blockchains exist side by side. This situation happens until a new block is mine. Whatever original contentious block was chosen by the new miner then becomes the only version of truth. The previous blocks then return to the mempool and are invalidated.
  2. We call these blocks that are invalidated and returned to the mempool stale blocks.
  3. Stale blocks occur when there are two miners who create a block at the same time. Eventually only one of these blocks become validated and the other block become invalidated and returns to the mempool (stale/ orphaned block)
  4. It is important to wait for 6 consecutive blocks as it is the only way to be sure that your transaction was not uploaded into a block that will later become stale/ orphaned.
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#3013
  1. What happens in the bitcoin network when two miners solve a block at the same time?

Both transactions are taken into effect and are linked to the block. The next block mined determines which block it links to, and the other is discarded. The other transaction is sent back to the mempool.

  1. What is a stale block?

It is an orphaned block that is on the shortest chain where there’s another version of that truth that has been accepted on the block.

  1. How do stale blocks occur?

Orphaned blocks occur when two transactions are mined with a nonce under the target.

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

Because a block can be an orphaned block and be dropped.

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#3014

  1. Then two blocks are circulating in the network. But only one of them will be accepted by the network, and that will be the one that blockchain is longest and more difficult.

  2. Stale block is the block that has been rejected by the network when 2 blocks at the same time were circulating in the network, however, only one of them has been added to the chain so another has been rejected cause there can be only one version of the truth so because of that the rejected block becomes a stale block.

  3. Two new blocks created, block A and block B -> they get both get propagated through the network and getting accepted by some nodes, chains are being created -> new miner comes in and wants to append his block C but he chooses the chain with block A in it, and appends it there. For that reason, block B is getting rejected from the network and it becomes stale block. Network chooses the longer chain to accept and network can have only one version of truth.

  4. Because then it is 100% confirmed transaction. And if we have more blocks that have confirmed our transaction it means that the block is not stale and it will be added to the chain without rejection.

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#3015

  1. Some nodes accept both blocks, but if the next miner decides to start on a block that is on a different node the chances are that the node will select the one with the longest POW .

  2. Stale blocks are blocks that were solved and added to blockchain but then dropped after the node chose the longest.

  3. They occur when 2 miners solve a block at roughly the same time, but only 1 gets chosen at the end. The losing miner then has there blocks dropped from the network.

  4. Its important because your transactions on your block can still be dropped, the rule of thumb is to wait 6 confirmations just to be certain.

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#3016

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

They wait for other miners and the longest chain wins.

2.What is a stale block?

It’s a block that remains or wasn’t linked in the blockchain.

3.How do stale blocks occur?

They occur when two miners complete the block at same time.

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

It is better to wait 6 blocks to be sure it is not a stale block.

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#3017

What happens in the bitcoin network when 2 miners solve a block at the same time?
Both blocks are linked to the previous block until one of them develops a longer chain. When other miners compete to add blocks to these two parallel blocks, whichever block has the next block added first will be confirmed and the other parallel block will be invalidated and its transaction returned to the mempool.
2) what is a stale block?
It is a block that has become invalidated.
3) how do stale blocks.
Added to the network concurrently with another block, they are invalidated due to the “longest chain protocol”. This means the other block was added to with further blocks by miners more quickly than this stale block.
4) why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
To get the transaction confirmed more quickly. Waiting will give greater probability that it will not be added to a stale block. Being returned to the merempool will delay confirmation. significantly.

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#3018
  1. What happens in the bitcoin network when two miners solve a block at the same time?

They are both propagated through the network to their closest nodes, then the first block to have another built on top of it will become the accepted version of the blockchain. The other block will be rejected and the transactions returned to the mempool to be picked up by miners again. The longest chain will always be the chosen one.

  1. What is a stale block?

A stale block, aka orphaned block, is the extra block that hasn’t been confirmed with additional blocks built on top of it.

  1. How do stale blocks occur?

As above - two accurate but different versions of the blockchain being propagated at the same time.

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

This adds security that the transaction has been enacted and is not going to become part of an orphaned / stale block.

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#3019

  1. When two bitcoin miners solve a block at the same time they perpetuate the solution (block) to their closest connected nodes, and two versions of the blockchain will persist for a time until the next block gets built on the foundation of one or the other, at which time the longest chain will become the confirmed chain, and the unchosen chain/block will be invalidated and that block solution will become stale.

  2. A stale block is a valid block solution that was perpetuated to other nodes, but was then superseded by another block solution, and is therefore ultimately rejected by the network. (why we wait for at least 6 confirmations)

  3. Stale blocks occur because there are always multiple valid solutions to creating blocks, and since different systems in different locations are working on them, they occasionally get put forward nearly simultaneously and are able to perpetuate on the network for a time.

  4. It is important to wait for more than one block to be confirmed when sending or receiving a transaction to make sure that those transactions are the ones that became part of the ultimately triumphant block, and not on some orphan spur and then had to wait to be validated on a different block.

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#3020
  1. What happens in the bitcoin network when two miners solve a block at the same time?

There are now 2 versions of the blockchain that exist. The new version is chosen based on which block the next miner chooses and completes first. The network now continues with this version of the blockchain because it is longer.

  1. What is a stale block?

A stale block is the result of 2 miners solving a block at the same time. When a miner successfully completes the next consecutive block and adds it to the blockchain, the other block is dropped and the network continues with the longer version of the blockchain. The old dropped block is called a stale or orphaned block.

  1. How do stale blocks occur?

Two miners solve a block at the same time. The stale block occurs because a miner successfully adds a block to the other version of the blockchain. The network continues on with the longer version. The shorter version has its blocked dropped. This is known as a stale or orphaned block.

  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 because your transaction might be in a block that is dropped.Having more confirmations helps to ensure your transaction will be accepted because miners continue to work on the longest version of the blockchain.

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#3021

1. Each miner will create his own version of the new block, each of the block will propagate in the network through the closest nodes. one of these blocks will become a stale/orphaned block and will be rejected from the blockchain as the other one was accepted.

2. Stale block is a rejected newly formed block by the blockchain as another block was accepted, the transactions/data in that rejected stale block will return to the mempool to be picked up by another miner.

3 Stale blocks occur when two or multiple newly formed blocks were propagated into the blockchain, only one of them will be accepted as it would be the longest link. stale blocks are confirmed blocks which were added into the blockchain but then it was rejected as the system choses the longest link after 6 confirmed blocks.

4 in order to avoid the formation of stale blocks which will lead the transactions back to the mempool.

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#3022

Homework stale blocks

  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?

1 The longest blockchain will win and the shorter one will be dropped and orphaned. This will be dumped into the mempool.
2 This block gets thrown back into the mempool , as another block that was made at same time had a longer chain. A fork happened.
3This happens when 2 miners mine a block at the same time.
4 More confirmation is good as you want to know that your transaction is accepted and not discarded due to a fork happening
5

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#3023

1. What happens in the bitcoin network when two miners solve a block at the same time?
A conflict happens because the Bitcoin Network now has two different versions of truth spreading around the nodes. Both proposed blocks are valid, but only one can be appended. The blocks in the longest chain will be valid and the others will be discarded (orphan or stale).

2. What is a stale block?
Stale Blocks are blocks that are no longer part of the current best blockchain because they were overridden by a longer chain.

3. How do stale blocks occur?
When a Bitcoin miner successfully finds a valid next block to append, that block gets propagated to the entire network, but first reaches the nodes that are geographically closest to where that block was discovered. It doesn’t take long for every Bitcoin node on the network to receive the propagated block. However, if two miners located on polar opposite ends of the globe successfully find a valid next block at the same time, we have a conflict on the network.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
To avoid stale blocks. However, after one version of truth is overridden, the transactions in the stale blocks are returned to the mempool to be picked up in a future block. Stale blocks are usually not a serious threat to the network but they do leave room for fraud and attacks on the network.

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#3024
  1. They both get propagated as valid blocks.
  2. A stale block is a valid block that has been dropped.
  3. When two blocks are solved at the same time, they each get propagated to different nodes who will consider them as valid. When the next block is produced, it will be based on on of those two previous blocks and will be propagated to all the nodes. When the nodes receive the new chain, they will keep it because it is the longest chain and they will discard the block that is not part of the new chain.
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#3025
  • What happens in the bitcoin network when two miners solve a block at the same time?

When 2 miners solve a block at the same time the block in the longest chain wins and the other block is discarded and considered a stale or orphaned block. All the transactions are returned to the mempool.

  • What is a stale block?

A stale block is the block that was in the blockchain but then dropped because another block that was produced at the same time was part of a longer chain.

  • How do stale blocks occur?

Stale blocks occur when a block was valid for a while because 2 were produced with the same version of the truth but then dropped because the blockchain continued on another block.

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

It is important to wait for 6 confirmations to be sure that the block your transactions are in is not dropped from the chain.

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#3026

  1. When two miners solve a block at the same time, the block chain splits and more blocks are added to each prong. But only one chain will be deemed TRUE and the other blocks not on that chain will be released into the mem pool.

  2. A stale block is a block that has been removed from the chain and placed back into the mempool.

  3. Stale blocks occur when it is on the shorter POW and thus deemed not to be true.

  4. It is important to wait for at least 6 blocks to be confirmed because then we know a stale block hasn’t occurred and it is deemed to be true through all nodes syncing through the POW.

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#3027
  1. the blockchain will fork till there are more confirmations on a certain block.
  2. a stale blocks a block that was not accepted into the block
  3. stale blocks occur when the hash rate is to low and the puzzles get solved too fast.
  4. confirmations help secure the blockchain and ensures that there are no hard forks
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#3028
  1. Both blocks will be added on to the blockchain. The next miner will choose one of the 2 previous blocks to add the next new block, which creates a longer chain. The shorter chain will be dropped.
  2. Stale block is a dropped block which was previously on the blockchain.
  3. When 2 blocks was added on there the blockchain, one version of the blockchain grew longer and being considered as the only version. The other block will be dropped and became a stale block.
  4. To prevent being dropped as stale blocks, it is good practice to wait until 6 more blocks are confirmed.
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#3029

Stale blocks can occur whenever, either when the hash rate is high or low.

Accidental forks are different than soft/hard forks. Hard forks are consensus upgrades and are intentional, while accidental forks occur in the network when two miners find a block at approximately the same time.
The reason why a user should wait for more confirmations when sending/receiving a tx is to make sure his tx doesn’t end up in a stale block. :slight_smile:

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