Digitálne meny a Blockchain

Key Stats

• Looking for open, unstoppable, peer-to-peer payments, for reasons mentioned earlier.
   
• We need to agree about all transactions in the system –-> to reach a consensus about the state of the ledger.
   
• We need to get an agreement securely, expecting some participants to come and leave at any time, and expecting some will try to cheat. This can be achieved in basic form through proof-of-work, which is chaining blocks of transactions.
   
• Since proof-of-work is hard, it must be incentivised.
   
• Hence, a crypto-currency is born.

So, why blockchain?

 A tamper-proof, shared digital append-only ledger that records transactions grouped into blocks in a decentralized peer-to-peer network. The permanent recording of transactions in the Blockchain stores permanently the history of asset exchanges that take place between the peers.

Updating the ledger (usually) requires solving Byzantine Agreements (hash) with economically incentivized participation, secured by cryptography

What is Blockchain?

1. New TX is broadcasted to the network
 

2. Each node collects TXs into blocks
 

3. In each round a random node is selected to generate a block
 

4. Other nodes accept the block if it follows the rules (valid signatures and TXs)
 

5. Acceptation of the block is expressed by including its hash into input data of the next block

Blockchain - synchronisation

Consenus Mechanisms

Proof of Work (Bitcoin)

Proof of Stake (PIVx)

Delegated Proof of Stake (NXT)

Practical Byzantine Fault Tolerance (Hyperledger)

Delegated Byzantine Fault Tolerance (NEO)

Proof of Importance (NEM)

Directed Acyclic Graph (IOTA, Hashgraph)

Blockchain Simulation:

1. https://anders.com/blockchain/public-private-keys/keys.html

2. https://anders.com/blockchain/hash.html

Non-fungible tokens (NFT)

Thank you!

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