Homework on Stale Blocks

1.When miners solve a block at the same time they are both valid until another miner picks up one of these, this becomes the longer and valid blockchain

2 .A stale block is a temporary valid block which transactions are returned to the mempool

3.When miners create two valid blocks at the same time and one block or series of blocks are rejected then stale blocks occur

4.It is important to wait for confirmations at least 6 so you are confident that the blockchain has propagated the block globally and your transaction has not been returned to the mempool

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Two conflicting versions of the blockchain are propagated on the network. Subsequent additions will be made to the longest blockchain, in terms of PoW rather than number of blocks added, until there is consensus across the network as to which blockchain is valid. Once consensus is reached the all other blockchains are ignored.

  2. What is a stale block?
    A stale block is one that was appended to a blockchain which has subsequently been invalidated and dropped.

  3. How do stale blocks occur?
    Blocks will continue to be added to conflicting versions of the blockchain until such time as full consensus is reached across the network. Only blocks appended to the winning blockchain will be validated and those on the losing blockchain will become stale or orphaned.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    To confirm which blockchain version has been accepted across the network. It is typical to wait for 6 confirmations before consensus is confirmed.

  1. They both go onto the network until one of the blocks has a new block added to it then the other block will be removed and the transactions in the removed block will go back to the mempool.

  2. A stale block are when 2 blocks are crated at the same time.

  3. When 2 blocks were created at the same time.

  4. To avoid a stale block that has your transaction in it returning to the mempool.

  1. whichever has the longest chain. The blocks that are not accepted become stale blocks
  2. Stale blocks are the blocks that get abandoned when another chain is created but not accepted as the “real” chain.
  3. Stale blocks happen when two miners solve a block at the same time.
  4. So it is safe to assume that the transaction you did in the block doesn’t become stale.

1. What happens in the bitcoin network when two miners solve a block at the same time?
Both blocks get attached to the previous block.

2. What is a stale block?
A valid block that has been rejected from the blockchain because the alternative chain has a longer size.

3. How do stale blocks occur?
When there is a competition between blocks, the next miner decides which one will be incorporated into the blockchain. The other block gets rejected and becomes a stale block.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Because the block in which our transaction is might become a stale block.

  1. There are, temporarily, two versions of the blockchain.
  2. The block in the version of the blockchain that is, eventually, not chosen to continue as the accepted version.
  3. When the other version of the blockchain has another block confirmed, it becomes longer, and is then the accepted version. The block in the blockchain that is not longer, becomes rejected and transactions are returned to the mempool.
  4. To make sure your transaction becomes part of the accepted version of the blockchain and not returned to the mempool.
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  1. the next block will propagate on one or the other and the transactions in the orphaned block will return to the mempool.

  2. a stale block is one that is not built upon by the following blocks.

3.to allow the network time to establish correct history on chain.

  1. When two miners successfully solved a block at the same time, the blockchain will have two competing blockchains. Any subsequent block appended to either one of the chain, the most POW chain be adopted .The shorter chain with the lesser POW will be dropped and all the un-mined transactions in the block will be returned to their respective mempool to be pick up by miners again.

  2. Stale block or sometimes known as Orphaned block, are blocks that failed to make it to the blockchain even though they are valid blocks. They are blocks that lost out to the other competing chain.

  3. Stale blocks occur because they are unsuccessful in forming the next chain

  4. the importance for waiting out for more block confirmations is that successful blocks can still be dropped at the very initial stage. The more confirmations there are, the more assurance that the block has been adopted in the chain.

  1. Two valid versions of the blockchain come into existence. Nodes closer to one version will accept that as the truth.

  2. A stale block is a block, that gets dropped, meaning that no more blocks will be appended to it. Transactions from a stale block will be returned to the nodes or become invalid (Ivan said both things).

  3. When a blockchain splits into two versions, because of two miners simultaneously finding their block, and then the following block gets appended to just one of the two versions, the other chain ends there resulting in that one block being dropped. It becomes stale or orphaned.

  4. If the transaction gets confirmed by only one block, there is a chance that the block containing your transaction will get dropped. Waiting for several (ideally 6) blocks to confirm your transaction, makes sure your transaction actually belongs to the longest chain and will not be invalidated or returned to the mempool.

  1. Two competing longest chains appeared. Need to wait for the next block to break tie.

  2. It is the block with transactions being returned to mempool because another longest chain found.

  3. So that our transaction is not being rejected due to being mined into a stale block.

1, 2, 3. The bock that gets a new block added will be the winner since it becomes the longest chain, while the other block becomes stale and its TX’s will be dropped back in the mempool.

  1. To make sure all stale blocks are dropped. The network need time to update their copies of the network.
  1. the chain will split in 2 temporarily
    2.a block that gets put back in to the mempool
    3.when a block is added to one of a forked blocks the one thats shortest gets dropped creating a stale block
    4.so there not a chance of a block becoming stale

What happens in the bitcoin network when two miners solve a block at the same time?
The block becomes temporarily forked. The block that is picked up first and built upon becomes the longer chain and therefore the acknowledged truth. The other block is dropped from the chain and becomes invalid. Its transactions are returned to the mempool for processing.

What is a stale block?
A stale block is the duplicated block is one that has been dropped from the chain due to simultaneous processing but failure to build upon in a timely fashion to be come the recognized chain continuation.

How do stale blocks occur?
When 2 miners process a block simultaneously and temporary fork occurs. The chain will continue and recognize the longest part of the chain, therefore the block built upon first becomes incorporated in the chain and the one not built upon becomes the stale block. That block is dropped and its transactions return to the mempool for processing into a new block.

Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
There is a chance that your pending transaction could be part of a simultaneously produced block scenario. If so, it could be that the block is dropped and becomes a stale block. These transactions are invalidated and sent to the mempool for processing again. 6 confirmations signify a confirmed transaction.

1 Nesse caso existirão duas versões diferentes da blockchain, que serão propagadas pela rede. Eventualmente uma das duas versões se tornará mais longa, conforme novos blocos forem criados e de acordo com a versão adotada pelo minerador.

2 É um bloco que em algum momento foi considerado a versão correta da blockchain, mas por não fazer parte da versão mais longa foi desconsiderado pela rede.

3 Quando dois ou mais mineradores mineram seus blocos em tempos muito próximos, irão eventualmente gerar duas ou mais versões corretas e paralelas da blockchain, os nodes vão aceitar a versão que for propagada a eles em primeiro momento. Quando a versão mais longa da blockchain for escolhida e aceita pelos nodes, a(s) versão(ões) menos longa(s) será(ão) abandonada(as) e seu(s) respectivo(s) bloco(s) será(ão) considerado(s) como stale block(s).

4 Para garantir que a transação não volte ao mempool, no caso de um stale block, é seguro aguardar algumas confirmações.

  1. It creates two different (both valid) blockchains that start streaming out in the network. At some point, after a few more blocks has been mined, one of the blockchains will become invalid and the blocks will be dropped since the nodes prefers the longest blockchain.

  2. A stale block is a block that was previously appended to the blockchain, but got dropped because of the version of the blockchain it was running got dropped.

  3. Stale blocks occur when the network decided which of the parallel running blockchains to choose as the right one to continue on. This is typically decided upon the length of the blockchain; which blockchain has the most blocks appended.

  4. Because you cannot be sure, after 1 block has been mined, that the blockchain your transaction was confirmed on will not get dropped later. The more confirmations (mined blocks) you receive on your transaction, the lower the chance is for your transaction to be pushed back into the mempool when the transaction’s block is dropped. The “golden” number here is 6. Wait for 6 confirmations and you should be good to go.

  1. The Block that gets to be the longest chain will be accepted, and thee other block will be orphaned and the TRX from the dropped block will be returned to the Mempool.
  2. A stale block or orphaned block, that has been rejected, a dead end because there is a longer chain.
  3. When there are 2 blocks being propagated at the same time through the network, although both true, one maybe has 2 confirmations ahead of thee other and is accepted before thee other and the latecomer rejected, by the network,.
  4. To see if it is accepted and not a stale block. 6 confirmation best practice

Stale blocks

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

Both miners will propagate their new blockchain through the entire network resulting in different sections of the blockchain network nodes tracking/replicating competing blockchain solutions.

Both solutions will exist within the network until the next block is appended to the blockchain resulting in one of the two competing blockchains growing in length with respect to the other.

Once one of the two competing blockchains is longer than the other blockchain record all nodes within in the blockchain network will track this new longer blockchain resulting in the node releasing their original blockchain ledger. Released blockchains are termed “stale blocks” or “orphaned blocks” with the transactions recorded within these blockchain returning to the mempool for later processing onto to end of the newly formed blockchain.

2. What is a stale block?

A “stale block” is a previously hashed block containing UTXOs which were not incorporated within the blockchain ledger. These released UTXOs are returned to the mempool for later processing within a new block to be added to the end of the blockchain.

3. How do stale blocks occur?

Two or more miners propagate their blockchain through the network resulting in different nodes of the blockchain network tracking/replicating competing blockchain solutions.

These competing blockchain ledgers will coexist within the network until the next block is appended to the blockchain ledger at which point one of the two competing blockchains will grow in length with respect to the other. Once the blockchain length is increased all network nodes will resort to tracking the new longer blockchain resulting in “stale blocks” (incomplete blockchains) being released by network. The resulting released UTXOs return to the mempool so that these UTXOs can be correctly appended to the longest blockchain ledger.

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

The blockchain network automatically adjusts the target difficulty (target number) to ensure the time taken to produce a newly hash block is maintained at 10 minutes. The value of the target number is inversely proportional to the number of miners competing within the network.

By maintaining the time taken to produce new hashed blocks to 10 minutes the number of competing blocks released to the blockchain ledger by competing miners is limited/restricted reducing the probability of coincident blockchains occuring at the same time. Also the time taken to resolve competing blockchain ledgers, and thus forming multiple coincident stale blocks, is reduced since all network nodes refresh their blockchain ledger every 10 minutes.

By waiting for the blockchain ledger to growth by 6 blocks 60 minutes have elapsed reducing the probability that your blockchain transaction was include included within a stale block and not confirmed.

  1. When two miners solve a bitcoin block at the same time, both are valid and propagated around them. It is an accidental fork. Two different chains are in competition until a new block is found and the longest chain becomes the valid one.

  2. A stale block is a block that was valid when created, but it was in competition with another valid block and it has been rejected because it was not in the longest chain. It is also described as an orphan block.

  3. Stale blocks occur after an accidental fork, they are the rejected blocks.

  4. It is important to wait for more than one block to be confirmed when sending or receiving a transaction, because you want to be sure that your transaction will not be in an orphan block (or stale block), in order to be sure that your transaction will remain valid forever.

1.One block will win out depending on how it propagated throughout the network and the miners that pick up on it.
2.A stale block is a block that was dropped. Those transactions then go back to the mempool.
3.When the blockchain chooses the chain with the most pow the other block gets dropped.
4.Your transaction could end up back in the mempool before it gets in the right block that gets added to the blockchain

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

The network is forked into two chains ending with either of the two solved blocks.
When new blocks are created and chained to either of them, then the network keeps the longer chain and drops the other.

  1. What is a stale block?

A block that is removed from the blockchain when there is a longer competing chain in the network.

  1. How do stale blocks occur?

When two blocks are created at the same time, then all new blocks that make a shorter chain with one of them become stale.

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

To ensure that the block is not stale.