A block chain is a growing list of records, called blocks, that are linked using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data (generally represented as a Merkle tree).
A blockchain is a decentralized, distributed, and oftentimes public, digital ledger that is used to record transactions across many computers so that any involved record cannot be altered retroactively, without the alteration of all subsequent blocks
A ledger is a permanent summary of all amounts entered in supporting journals which list individual transactions by date.
The video below is easily the best I have found explaining blockchain. I would suggest you watch it several times.
The video below is good high-level overview of blockchain, but doesn't hold a candle to the video above. If there was a nobel prize for awesome videos, the video above would deserve it.
Start here to understand blockchain
- Trust and Currency
- Hashing (related to this is cryptographic hash, collision resistance, determinism, one-way function and entropy).
- Digital signature (related to this is key pair generation and SHA256)
- Block (related to this is Block header and Candidate block)
- Mining (related to this is miner, nonce and proof of work)
Other ideas in blockchain
- Immutable transactions
- Merkle proof
- Merkle tree
- 51% attack
- Genesis block
- Transaction pool
- Self-referential data structure
- Distributed consensus
- Double-spend problem