Summary of Bitcoin Whitepaper
I believe that bitcoin is a well defined well define cryptocurrency. It make all the cryptocurrency be able to trace to make all cryptocurrency valuable. It take part of the hash header from last block to build next block, so all the block is chained together.
We have to choose the node called miner who record the transaction. If we chose the node randomly, it may face the sybil attack and destroy the whole blockchain by taking all the chance of record transaction and counterfeit the transaction. Therefore, consensus it mention in the blockchain. In bitcoin, it is POW, by scanning a value with hash. The value is begin with numbers of zero which is used to control the difficity of the puzzle.
Bitcoin calculate the probability of defecting the POW. Malicious node will end up with Gambler’s Ruin problem, if the probability of choosing honest node is larger. This concept is also know as 51% attack which means that we have to defect the blockchain with lager probability being chose as a miner. It show more result with Poisson distribution, so we can know that with only 30% probability being chose, it only got 17.77% to make attack successful.