Digital Currencies & Blockchain

Inflation Rate - 2018	3.85
Inflation Rate - 2019	3.7
Current Block Reward	12.5 BTC
Next Halving Date	May 2020
Next Block Reward	6.25 BTC
Total BTC Mined	18 000 000
Total BTC Mined (%)	85
Blocks per day	ca. 144
BTC Mined per day	ca. 1800 BTC
Blockchain Size	250 GB
Total nodes	ca. 100 000

Key Stats

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. Transaction is broadcasted

2. Each node collects transaction into blocks

3. Each round a random node is selected to state the "truth"

4. Other nodes accept it only if certain conditions are met

5. They express acceptation by including the block's hash into their next blocks

Blockchain - Consensus

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)

Compensate the bitcoin miners for securing the network
- making it economically infeasible for attackers to flood the network with transactions
Fees also serve as a security mechanism themselves
Most wallets calculate and include transaction fees automatically
- more inputs --> higher fee
Calculated based on the size of the transaction in kilobytes, not the value of the transaction in bitcoin
Fee market