The blockchain industry is in full swing and the best way to understand how it functions is by creating it yourself. Simplistic examples can be revealing. Below you can find my own 5-cent implementation which helped me grasp the concepts.

A chain is a glorified linked-list with blocks keeping a hash of the previous block. As such one cannot fiddle with the content without cascading the effect down the list. Here a block definition:

You don’t need to encode the whole package in the hash and a good hash is an art on its own.
The chain is really just linking blocks together:

A node is part of a peer network where each attempts to solve a puzzle. The type and complexity here is a whole topic related to attacks, spamming and balance between protecting and challenge. Let’s say that the puzzle should be fairly difficult and that whoever finds the solution is being rewarded. Note that if you are only after a blockchain storage solution you don’t need to solve any puzzle, the chain’s linked hashing is all you need. Once a peer is rewarded the other peers are notified and get an update. The puzzle is difficult to solve and easy to proof, hence the reason why cryptographic algorithms are perfect. It’s easy to show that a solution is right but it’s tough to find it.

The blockchain idea is great, the whole money-making scheme much less. The fact that the (complex) computation is irrelevant and not being used for anything else is a disgrace, a waste or resources and time. If only the CPU cycles would be used to compute protein folding or something alike, but the scheme is purely geared towards enrichment.