A cryptographic hash function is a one-way function. There is no way to extract the original data out of it. The better we get at writing these functions, the less likely it is that there will be a collision. That are two pieces of different data resulting in the same hash.
In this introductory episode, we discuss what makes up blocks and block headers. We also cover a bit about state vs history, what exactly makes up a transaction and do a quick intro to a Merkle Tree.
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