Proof of Work Assessment 4

1.What would an attacker need to do to modify a previously mined block? What is one of the factors that prevent this from happening?

To modify a past block, an attacker would need to redo the proof-of-work of the altered block and all subsequent blocks at a rate faster than honest nodes in order to catch up with and surpass the work of the honest chain. This is made difficult due to the public nature of mining and the subsequent unalterable evidence of criminality.

To modify a past block, an attacker would need to obtain the private key used in the transaction they wish to alter. This is made difficult due to the private nature of transactions and the subsequent unalterable ability to modify blocks.

To modify a past block, an attacker would need to redo the proof-of-work for that block. This is made difficult due to the public nature of mining and the subsequent unalterable evidence of criminality.

To modify a past block, an attacker must redo that block’s proof-of-work and win all new blocks being discovered simultaneously.

2.How does the Bitcoin network maintain a steady rate of block discovery despite the increasing capability of mining hardware?

As long as the blocksize is large enough to accommodate network activity then blocks will remain on schedule.

The increasing capability of mining hardware has no effect on the rate of blocks being discovered just on the speed in which they are solved.

Non-mining nodes ensure that miners do not try to increase the rate of block discovery.

The network uses a difficulty algorithm that adjusts the network difficulty to maintain a steady rate of block discovery no matter how much hashpower is applied to the proof of work process.

3.What is the difficulty adjustment period described in the whitepaper that BitcoinSV will return to?

Every twenty-six blocks

Every other block

Every block

Every 2016 blocks

4.In order to allow for node operators who invest in more ________ i) to help discover more valid blocks through the proof of work process, the network uses __________ ii) to maintain a steady rate of block discovery no matter how many __________ iii) to the proof-of-work process.

i) bitcoins, ii) a provably fair lottery, iii) nodes are contributing

i) efficient hardware, ii) an algorithm that adjusts the network difficulty, iii) CPU cycles are applied

i) hash power, ii) a throughput handicap, iii) transactions are entered in

i) nodes, ii) a difficulty adjustment algorithm nodes are contributing, iii) nodes are being used

5.How is the Proof-of-Work difficulty determined

The proof-of-work difficulty increases based upon the blocksize.

The proof-of-work difficulty is determined by the amount of nodes on the network with the difficulty increasing as more nodes join the network and decreasing as nodes leave the network.

The proof-of-work difficulty increases with time for the duration of the Bitcoin network.

The proof-of-work difficulty is determined by a moving average targeting an average number of blocks per hour. If they're generated too fast, the difficulty increases.

6.What is the current difficulty adjustment period for BitcoinSV?

Every other block

Every block

Every twenty blocks

Every week