Research about blockchain technology, type of attacks and solutions

In the 4.0 technology wave, Blockchain is considered by the technology world to be the most noteworthy advancement after the birth of Internet. The findings of this paper will find out about Blockchain and Bitcoin Cryptocurrency. Along with that, we will mention to a weak point of Blockchain- Double spending and research on security against attacks including Double spending hypothesis attacks and attack resistance in practice help Blockchain apply for Bitcoin cryptocurrency.