Homework on Stale Blocks

Blockchain and Bitcoin 101
#21
  • What happens in the bitcoin network when two miners solve a block at the same time?
    At this point there will . be 2 separate and distinct blocks appended to the Blockchain
  • What is a stale block?
    A stale block occurs when two blocks are appended to the . blockchain at the sametime and thereafter the block that has subsequent blocks appended to it, over the next hour, will become the longest blockchain, at which point the other . block will become a stale block and eventually the transactions in that block will be returned to the mempool.
  • How do stale blocks occur? Stale blocks occur when two seperate blocks are appended to the blockchain at the same time.
  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? Waiting allows the block to . become embedded in the chain and by doing so avaoids becoming a stale block.
    [/quote]
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#22
  1. At a certain point the there might will be a split into two versions of the block.
  2. This is the rejected section of the split blockchain.
  3. The longest section of the blockchain will be accepted by the network as the valid chain, hereby rejecting the competing section, rendering it to stale blocks.
    4.To reduce the risk of mining on a possible stale/orphaned blockchain section
#23

1- Both blocks would be added to the network and brodcasted
2- Stale block is a dropped block from the network what was added then ignored because another block has been counted by the network
3- when two miner able to append their mined block to the network at the same time
4- to minimize stale blocks

#24
  1. Two different version of blockchain will be propagated till the network has chosen one over the other.
  2. This is valid block which has been rejected because the network chose a different block to connect to the chain.
  3. This can occur when different miners mine more or less simultaneous different blocks.
  4. This is to be sure that your transaction is not in a stale block
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#25

You answer questions really well.

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#26

1 Each block start to propagating through the nodes
2 Almost the same that an Orphan block, a valid block who has been discarded and “rolled back”
3 After the propagation of two diferent valid blocks for the same position of the blockchain, eventually the next one… or several more will determinate the biggest chain, and will discard the blocks (stale blocks) that dont match.
4. Because the posibility of the stale blocks, that your tx will be rolled back to the mempool

#27

  1. When two miners solve a block at the same time in the bitcoin network, they both start to propagate their valid blocks locally. Eventually, one blockchain will prevail when a new miner solves the next block and places it on either blockchain.

  2. A stale block is a block that has been discarded from the blockchain but was previously added to a different but also valid version of the blockchain.

  3. Stale blocks occur by becoming a valid block but being initially created around the same time as another miner creating a block (both finding a solution at the same time). The next block that is found as the next block in the sequence is placed on the end of someone else’s block. This miner’s block that is chosen to be appended to is the winner, and their block is added to the blockchain which is now the valid blockchain because it is the longest. The other miner’s block that has not been further added onto is now discarded because that version of the blockchain is shorter and now invalid.

  4. It is important to wait for more than one block to be confirmed when sending or receiving a transaction because your transaction may be nullified if it’s part of a stale block. The more confirmations you wait, the less likely it is to be in a stale block. At six confirmations, it’s extremely unlikely you will have the transaction reversed because of a stale block.

#28
  1. The less difficult block will return to the mempool.
  2. A successfully mined block, but was not
    accepted into the chain.
  3. Another block at same height had it chain extended first.
  4. So there is enough time that the block state can propagate through the network.

(SOURCE: https://bitcoin.org/en/glossary/stale-block)

#29

  1. Both blocks are added to the closest nodes. This creates a dual reality for the blockchain.

  2. A dropped block that was sent to the mempool.

  3. When two blocks have been verified by the system at the same time, one of these blocks will eventually have to be eliminated. The next block will be added to one of these two blockchains. The block that did not receive this new block onto its chain will be dropped and sent to the mempool. Then entire system will then adjust to reflect the block that has the longer chain.

  4. To make sure that your transaction is not in a block that will be dropped.

#30

1 the network will choose longest chain and other block will go to mempool.
2 stale block is block who was in blockchain before.
3 , it occur then new block choose other previews block.
4 to be sure 100% what that block will be up proof.

#31

  1. Both blocks will be propagated across the network. When a new block is mined, miners will add there block to one or other of the blocks this will continue until one of the chains is longest. The longest chain will be confirmed and the transaction from the other block will be returned to the mempool.

  2. A stale block is an otherwise valid block that is rejected because another valid block mined at the same time has formed the longest chain.

  3. A stale block happens when more than one miner mines a block simultaneously. The block that goes on to form the longest chain is confirmed and the other becomes a stale block.

  4. In case your transaction ends up in a stale block and is returned to the mempool.

#32
  1. They create two different versions of the blockchain and start propagating their own version until a miner picks up one of the two as base for the next block, and the blockchain will keep as valid the chain with the most proof of work
  2. A stale block is a block that has been mined at the same time as another one and that has been dropped from the chain in favor of another
  3. When two miners solve a block at the same time and one of the two is dropped
  4. Because the wallet could be accessing a sequence of blocks that are only valid to the nodes it has interacted with but that are part of a version of the blockchain that has been dropped by the network
#33
  1. Only 1 block gets accepted on the blockchain and it is the longest block that will be accepted.
  2. Stale block is block that got rejected if miners was mining same block.
  3. When miners mines same block.
  4. To make sure that your transaction get accepted to the block and block to the blockchain. To make sure it didn’t appeared on stale block
#34
  1. Those two blocks will create a split in the chain and it’s up to the miners of next mined blocks which of the “duplicated” blocks hash is used as input for the new blocks to create the longer chain and turn one of those blocks stale
  2. A stale block is a block that was once a valid block but lost in “the race” for the longer chain
  3. Stale blocks occur when there’s blocks mined with the same height but they do not become part of the longer chain and therefore stale
  4. To make sure the transaction is part of a block that belongs to the longest chain and doesn’t become stale. Also if someone is attacking the chain and trying to double spend in the new blocks.
#35

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    In this case, there will be 2 versions of the blockchain for some time until another miner solves the puzzle based on one of these two blocks. This will make the blockchain with an extra block valid because it’s longer and the other version will be dropped (the block is rejected).

  2. What is a stale block?
    Also called orphaned block, this is a valid block that got dropped on the rejected version of the blockchain.

  3. How do stale blocks occur?
    When a miner solves a new block based on one of the two “twin” blocks, it creates a longer version of the blockchain. The other version is rejected and that block gets dropped (stale block).

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Because of cases like in question 1, it is better to wait for 6 confirmation blocks just in case the tx is in a block that might be dropped and gets back on the mempool.

#36

1-What happens in the bitcoin network when two miners solve a block at the same time?
They are placed in the chain and two momentary versions of the truth are created.

2-What is a stale block?
It is a block that was dropped by the network when not being confirmed. Transactions return to Mempool.

3-How are rancid blocks produced?
When a “longer” chain is identified, and a version of the truth is achieved.

4-Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
In order to maintain the order of the blockchain, not having a large number of orphan blocks and most importantly a version of the truth.

#37
  1. They both get added to the blockchain creating two valid blockchains. Only in time the longest blockchain will be the valid one and the txs of the orphan/stale blocks will return to the mempool.
  2. A block of an unvalid (shortest) blockchain of which the tx’s are returned to the mempool.
  3. When miners propagate new blocks at the same time and they are both added to the blockchain creating two blockchains to which other blocks are added until the longest version wins.
  4. To ensure that your tx is included in a block of a valid blockchain and not in a stale block.
#38
  • What happens in the bitcoin network when two miners solve a block at the same time?
  • the block in the longest chain will survive. The other will be disregarded and transaction list will be sent to the mempool
  • What is a stale block?
  • a stale or orphaned block is the block that is disregarded when two blocks are created at the same time in different place on the globe.
  • How do stale blocks occur?
  • a stale block will occur when this block was disregarded
  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
  • to make sure that the transaction data was not part of the stale block. That would mean it will take longer to confirm. Make sure to have 6 confirmations therefore.
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#39

  1. When two miners solve a block at the same time, both blocks will be propagated simultaneously through the network. A node’s location, in relation to the locations of the two miners, will determine which block it receives and adds to its version of the blockchain first. This will result in two different versions of the blockchain (in terms of the last block) exisiting temporarily in the network.

  2. A stale block is a block that has been validated by a node but does not form part of its active chain. If it was initially appended to the node’s active chain, on becoming a stale block its transactions are returned to the mempool. While a block is stale its transactions are effectively unconfirmed.

  3. Stale blocks occur when two different versions of the blockchain (in terms of the last block) have been confirmed in different parts of the network, but then a new block is mined for one of these versions and propagated throughout the network sooner. When this new block is validated by nodes and appended to its corresponding parent, the network will quickly accept this longer branch as the active chain. The block at the tip of the other branch becomes a stale block.

  4. When sending or receiving a transaction, it is recommended you wait for 6 blocks to be confirmed. You can then have complete assurance that your transaction has been included in the confirmed version of the blockchain, and there is no longer any risk of it ending up in a stale block and being returned to the mempool.

#40

1 some nodes will acknowledge the solution of minor 1 and some the one of minor 2

2 stale /orphaned block is a block that later gets removed/abandoned because of the scenario above. the next block after the one with 2 solutions will continue with one of the previous solutions. The second one (which is per se also true) will get abandoned.

3 when 2 miners solve a block correctly at the same time

4 the scenario above can happen at any time but we need the 6 confirmations (approx 10mins) to see if we dont get any stale/orphaned blocks.