This README introduces the main technical concepts to understand Distributed Ledger Technologies, the umbrella term for emerging Blockchain and Direct Acyclic Graph (DAG) technologies.
Why: For security and enabling "correct" consensus
What: The resulting hash that "proofs" that a certain amount of computational power has been invested
More detailed explanations: Wikipedia bitcoin-wiki
One of the best ways to really understand it - implement one yourself:
Recommendation: First try to implement it from scratch, then look at an example in a different language from your implementation and redo it.
Why: Required for decentralization
What: A dynamic way of reaching agreement in a group
Why is achieving consensus so difficult?
-> Starting point: Two generals problem
Amazing E-Mail from Satoshi in 2008 explaining how consensus & proof of work play together:
Email: Proof of Work to solve consensus in the Byzantine Generals Problem
Short explanation with visuals
Consensus in Blockchain Systems in short (Medium Article)