Homework on Stale Blocks

Blockchain and Bitcoin 101
#81

  1. Two chains split off until the next time a block is not simultaneously added to the blockchain.

  2. A stale block is a block that from one of the chains the ultimately is rejected.

  3. Stale blocks occur when one of the chains is resolved as being the longest chain when the next block is produced.

  4. It is important to wait for more than one confirmation in case your transaction is included in a stale block.

#82

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Two valid blocks with a low enough nonce depend on new miner to base their block on the one they solved to continue the chain.

  2. What is a stale block?
    Stale blocks are blocks that have not been propagated to the chain.

  3. How do stale blocks occur?
    stale blocks occur when Blocks are produced to quickly and another miner continues on another block, therefore leaves that block dropped.

  4. 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 more than one block to be confirmed when receiving a transaction because your transactions could be in a block that is being dropped.

#83
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Two different versions of the blockchain get propagated through the network. The longer chain (when the next block will be added) will survive.
  2. What is a stale block?
    It’s a block that was in the blockchain for a short period of time and then gets dropped of the chain.
  3. How do stale blocks occur?
    They occur when there are two competing versions of a blockchain (when two miner mine a block at the same moment and propagate it through the network) - while one will survive, the other versions block will get dropped of the chain and the transactions will go back to the mempool.
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Because your transaction could be in a stale/orphaned block. After several blocks you have a very high degree of assurance that your block can’t be stale/orphaned.
#84

  1. When two miners solve a block at the same time the blockchain splits into two directions. Both blocks are valid. If a miner starts adding to one of the blocks and completes it before another miner builds on the other one then the longest will be accepted and the other put back into the mempool.

  2. A stale block was a block that was on the blockchain but was later put back into the mempool because a longer version of the blockchain was accepted by the nodes.

  3. Stale blocks occur when a valid block is no longer considered valid. a miner added to the other version first therefor rejecting the other block returning it’s transactions to the mempool

  4. It’s important to wait for more than one block to be confirmed when sending or receiving a transaction because it takes time for all the nodes to get the updated version of the blockchain. If there was another valid block you have to wait and see which one gets added onto first thus making the slower one to be rejected by the nodes.

#85
  1. Miners will propagate their blocks and two versions of the blockchain will coexistent for a short period of time until a new block is mined.

2/3. A stale block is an orphan block which have been mined in the same time as an other block but is not valid anymore because it s not a part of the longest chain. The other valid chain has one more block than the one where the stale block so this block get the status of orphan block.

4.It’s important be cause with one confirmation you are not sure that your block will still be in the longest chain. It can be discard if an other block have been mined in the same time and your transaction is not a part of it. It is a good practice to wait for 6 blocks.

#86

The Blockchain with the most PoW gets accepted and the other one tx’s get returned to the mempool

The block that gets returned to mempool

They are blocks that get dropped from Blockchain in favor of blocks with more PoW

It gives time for acceptance and propagation to the network

#87

  1. They are both valid until a longer chain is recognized. The longer chain will then be added.

  2. A stale block is a perfectly valid block that has been appended to the network but superseded by a parallel longer chain.

  3. Stale blocks occur when a chain is superseded by a longer parallel chain that has more blocks added to it.

  4. Because there is still a chance it could be superseded.

#88
  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 there will be two different chains will propagate through the network until a miner adds a new block to one chain making it the longest chain by difficulty. This chain will be propagated and accepted, and the other chain will be ignored and the block transactions will be returned to the mempool.
  2. What is a stale block? A stale block is a block that was in the blockchain at one time and has been dropped due to being on the shorter of two versions of the blockchain.
  3. How do stale blocks occur? A validly mined block is created at the same time as another competing block. Both of these blocks will propagate across the network creating competing chains.
  4. 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 more than one block to be confirmed when sending or receiving a transaction since it is possible that your transaction may be part of a block that becomes stale.
#89

  1. Both those miner’s valid blocks will be propagated throughout the network at the same time. There will be two valid blockchains with both blockchains having identical blockchains except for the last block which will be on different branches. The next block mined will determine which of these two chains is the valid blockchain to follow as it will be the longest blockchain.

  2. A stale block is a block that was properly mined and is now no longer valid since it wasn’t on the longest chain. All transactions in that block will be returned to the mempool.

  3. Stale blocks occur when a miner mines a valid block but that block resides on a chain that no longer is part of the longest blockchain.

  4. To avoid having your transaction being in a stale block and then returned to the mempool as an unconfirmed transaction. The more confirmations received the more secure the block. You should typically wait for 6 confirmations to be absolutely certain.

#90

Hello,

  1. When two miners solve at the same time the new block, they start propagating their result to the nodes, reaching a situation in which half of the nodes have one block, and the other half has the other new block. Eventually, the miner of the following block will use the hash of either one of the competing chains, leaving the other behind. the longest chain will be favored, the “orphan” block dismantled and its contents will go back in the mempool.

  2. A stale block is a block that, even though is complete, it gets abandoned in favor of the competing block. In other words, no more blocks will be built on the basis of the orphan block, because the longest chain will be favored by the nodes.

  3. Eventually the following miner will build a new block on either one of the competing blocks, making the chain longer. The longest chain will be taken by the nodes, the other, whose final block is the stale (or orphan) block, discarded.

  4. One must wait for more than one block because the btc he is receiving could be on an orphan block that will be discarded later. in this example, the transaction will have never happened , but one might have already released the goods in the real world.

Best

#91

1 both blocks are propagated through the network and miners will keep mining the new block until a new block is added. At the end the chain with the most transactions will win and the other block will be dropped, these transactions are returned to the mempool

2 a stale block or orphan block is a block that was accepted by the network but later rejected because another block that was accepted at the same time was propagated more and had more transactions.

3 They occur because two miners resolved the puzzle at the same time, their hash was under the target and accepted. But the system later has to reject one of them because only one version of the truth can prevail.

4 To make sure the transactions is not rejected because it was included in an orphan or stale block. (and therefore put back in the mempool)

#92

1, When two blocks are solved at the same time, these will get broadcast out to nodes. Both blocks may be valid.

  1. A stale block, is a block that has been dropped from the network and the transactions returned to the mempool.

  2. When 2 blocks are produced at the same time, which both might be valid, the block that will remain on the network will depend on the next miner who produces a block. The longest chain will always be accepted by the network, so any blocks on the shorter chain will be disregarded.

  3. To ensure that you have multiple confirmations and that the block does not get dropped.

#93

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Both are added to the blockchain creating two separate instances but only one version of chain will continue with the next block.

  2. What is a stale block?
    The other chain containing the block that was unused by the next block will then be removed and the transactions in that block will be released back to the mempool to be added to a different block.

  3. How do stale blocks occur?
    When the longer of two chains gets the next block the other shorter chains block is dropped.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    To make sure it is not going to be sent back to the mempool from being mined into a stale block, wait for 6 confirmations.

#94

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

There will be two separate forks of the same chain. This happens from time to time, where the network can’t agree on which chain is the real chain for a short period.

However, after another block is mined, it will add it to its current chain and the rest of the network will accept the longer of the forks. It is very rare to have forks longer than a couple of blocks high.

2. What is a stale block?

Blocks which were successfully mined but which aren’t included on the current best block chain, likely because some other block at the same height had its chain extended first.

3. How do stale blocks occur?

Stale blocks occur when the blockchain forks, but another competing block at the same height ends up parenting the new longest chain.

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

All public blockchains make use of blockchain confirmations. These are important since they can help you understand how confident you can be when making a transaction. When any transaction is first broadcast to the blockchain it starts with zero confirmations. This number then increases as the information is added to the first block, confirmed, given a permanent place, and followed by more blocks.

Blockchain confirmations are vital since they are a way of verifying and legitimizing information that will then become immutable. If a transaction is deemed fraudulent, it will be rejected from the blockchain: zero blockchain confirmations means zero transactions.

On average, cryptocurrency exchanges require a minimum of three confirmations until a transaction is accepted. Coinbase, for example, does not consider a Bitcoin transaction as final until it has received at least three confirmations.

However, the larger the transaction, the more blockchain confirmations are required. This is because the more confirmations there are, the harder the transaction is to reverse. For a transaction of $1 million, it’s not uncommon to wait for at least 60 confirmations. The amount of blockchain confirmations required to verify a transaction varies by blockchain.

#95

  1. The miner that solves the following block will add their block to one of the previous 2 miners blocks and the longer chain will then be adopted by the rest of the nodes.

  2. A valid block that is removed because another, longer, version of the blockchain has been adopted.

  3. When more than one miner solves a block, but the blockchain continued on another miners block. The stale block (reward and transactions) is then put back into the mempool.

  4. In case there is a stale block situation.

#96

  1. it creates a temporary fork in the chain that gets resolved when the next block is mined and added to one of the new blocks the other will be dropped and its transactions added to the mempool.

  2. a block that was mined and added to the chain but didn’t get enough confirmations so it was dropped from the network.

  3. when blocks are created quickly and not synced fully across the network it can create a fork in the chain resulting in the shortest chain getting dropped from the network.

4.to make sure that your block is not orphaned by the network.

#97
  1. If two miners produce a block exactly at the same time, the nodes closest in location to each miner will receive the block in their version of the ledger. This creates a split ledger even though the transactions are valid.
  2. Miners need to wait for at least six confirmations before ensuring that their block will not be dropped. The dropped blocks are called stale or orphaned blocks.
  3. The dropped blocks are called stale or orphaned blocks. This occurs when a version of the ledger is rejected. The block’s transactions are then sent back to the Mempool.
  4. A confirmed transaction is a transaction that is included in an appended block. In reality it is best to wait for six confirmations. Miners need to wait for six more blocks to be appended to the blockchain before assuring that their block was really appended to the valid version of the ledger. The miners will always accept the version of the ledger with the greater number of blocks. Miners need to wait for a least six confirmation before ensuring that their block will not be dropped.
#98
  1. There will be 2 BCs
  2. A block that is not part of the longest (Accepted) BC
  3. If there is a miner that has an out of date version of BC and appends block to that
  4. So that there is enough time for everyone to receive the block and append it to their local versions of the BC. Basically so that everyone will have the same version of the BC by the time a new block is mined,
#99

• What happens in the bitcoin network when two miners solve a block at the same time? Sooner or later, another miner will have a new block and adds its block to its chain. This chain has become the longest block chain. The network will use the longest block chain; those other blocks are disregarded or orphaned. All of the TX in the disregarded block will be returned to the mempool. (Ah, question: what if a TX was confirmed in the longest blockchain?)
• What is a stale block? It is a block that is disregarded because it is part of a shorter blockchain.
• How do stale blocks occur? When two miners solve their puzzles and add their block to their own blockchain. The two chains exist until a third miner comes along and creates a longer blockchain.
• 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 the TX has been ‘confirmed’ may be orphaned in the near future.

#100

  1. The first miner’s block is propagated through the network, and so is the second miner’s block. But these two block are not identical, some of the transactions picked by the miner can be different, and the propagation throughout the network and throughout the world varies as well. So we will have two competing chains of blocks (a kind of hard fork). The rule in blockchain is that the longest chain prevails, so we will need to wait for a third miner to choose the chain where he wants to append his block, the chosen chain of blocks will prevail, and the other blocks will be dropped and sent back to the mempool.

  2. A stale (or orphaned) block is a block that was successfully mined but was dropped by the network because its chain was overriden by a longer chain that was adopted by the network (for example when two blocks are mined almost at the same time).

  3. When two blocks are found by two miners almost in the same time, one block is appended to the best blockchain (after a third miner choose one of the two chains to append his block), and the other block becomes stale.

  4. To ensure that the block will not be dropped shortly thereafter and the transactions sent back to the mempool.