Lightstreams development team is presenting the principles of the Blockchain development and our tech stack

1. Blockchain Introduction
By Lightstreams
ETSIIT (UGR) , 13 March, Gabriel Garrido, Lukas Lukac
Follow us on Twitter
@lightstreams_io

2. Index
1. History (Español) - 10m
2. What is Blockchain (English) - 20m
3. Consensus (English) - 10m
4. Ethereum (English) - 20m
5. DApps (Español) - 20m
6. Lightstreams Tech Stack (Español) - 20m
7. Q/A (English/Español) - 15m

3. About us
Lightstreams is a small start-up of the blockchain industry.
● Started at 2017
● Won the “Consensys NYC Hackathon” by a demonstration of the
permissioned blockchain protocol
● 6 people working in two locations: Palma (Spain) - Düsseldorf (Germany)
● Permissioned blockchain protocol to empower content creators to
monetise their intellectual property data

4. History

5. Cryptocurrencies (tokens)
Utility Token
- Only good for spending at the issuer’s “store” (cassino tokens)
Currency Token
- Are meant to be spent on the daily transactions of life (coins)
Security Token
- Acts as a holder of value, sort of like a digital stock (company stocks)

6. What is Blockchain?
Blockchain is a public DATABASE with hell of a good backup.
- replicates (optimally) with each new user (hence p2p)
- mathematically, cryptographically ensures the rows can't be edited or
removed once inserted
“append only log of events”

7. Blockchain is made of blocks
Block = Header (info) + Payload (an
array of transactions, TXs)
Chain:
Block 1 +
Block 2 +
…
Block N.

8. What is a Transaction?
Change of state.
Example of a payment TX:

9. Transaction is like an Event
NEW_USER,
NEW_STATUS,
NEW_PURCHASE,
NEW_TRANSFER,
NEW_LIKE,
NEW_UNLIKE

10. Immutability
blockchain := event-sourcing - deletes
PERFECT AUDIT.

11. The magic
behind
immutability

12. Immutability Visualised
Image Source: dummyprogramming.com

13. How blocks are exchanged between peers?
Node := One blockchain instance, a device with a unique identity (peer with its
own Private Key)
Consensus := An algorithm deciding what transactions, blocks are valid and
what peers are trustworthy

14. Proof of Work Consensus
sha256(Block{TXs...}) => 000000dfs5d4f56sd4f56s4fd56
Consensus Rule:
IF block hash starts with 6 zero then is VALID and the block is added to the
chain.

15. Proof Of Work - PROs
Pros:
- Anyone can become a miner but that's also not really true due to
hardware requirements

16. Proof Of Work - CONs
- Majority of Mining done from China

17. Proof Of Work - CONs
- Majority of Mining done from China
- The transaction speed is between 10 mins to 1 hour

18. Proof Of Work - CONs
- Majority of Mining done from China
- The transaction speed is between 10 mins to 1 hour
- Very hard to scale as the core design is based on mathematical difficulty

19. Proof Of Work - CONs
- Majority of Mining done from China
- The transaction speed is between 10 mins to 1 hour
- Very hard to scale as the core design is based on mathematical difficulty
- Waste of resources

20. Who uses Proof of Work?
Most famous blockchains:
- Bitcoin
- Ethereum

21. Who uses Proof of Work and suffers scalability
issues?
Most famous blockchains:
- Bitcoin
- Ethereum

22. Ethereum
Ethereum is a decentralized platform, blockchain that runs smart contracts
(programs)

23. Smart Contracts
Deterministic programs deployed in EVM.
- code functions, typical programs but written in special language, Solidity
- can interact with other contracts
- make decisions
- store data
- transfer funds (send Ether)
CAN NOT COMMUNICATE WITH PROGRAMS OUTSIDE BLOCKCHAIN WORLD.

24. Wallets
Software for managing your account, its private key and therefore your virtual
funds, Ether/Bitcoin/XRP.

25. Solidity
Solidity is a high-level language for implementing smart contracts. It was
influenced by C++, Python and JavaScript and is designed to target the
Ethereum Virtual Machine (EVM).
- Statically typed
- Supports inheritance
- Importing libraries
- User defined types (classes)

26. Remix
Writing smart contracts in cloud

30. Decentralized Applications (Dapps)
● Centralized application
● Server-based
● Netflix
● Decentralized application
● Peer to Peer
● Popcorn (Bit-torrent)

31. DApps in Blockchain
Type 1
Blockchain
Type 2
Protocol
Type 3
Application
DApps need to be built around logics which involves token exchanges and
those tokens need to bind to a real value.
The application must be completely open-source and it must operate
autonomously with no single entity controlling.

32. Quick DApp Example
Goal: A company wants to adapt an open-source project to its own company
requirements.
Description: Company forked original repository and created the list of task
to be develop.
Requirements: Limited funds to accomplish this development. It wants to
encourage open-source community to work on this project.

34. DApps, everything is good?
PROs
Transparency Code is
open-sourced
Reliability Every node is a
backup. No require central
entity
Security Every transaction is
signed and immutable
CONs
Speed Tx finality ~6 minutes. 15
TPS
Expensive ~0.02 USD/tx, ~3.15
USD/Smart Contract
Complexity Limited data
storage, upgrades are hard,
mistakes are expensive

36. Lightstreams Tech Stack
Lightchain: Lightstreams implementation of a proof-of-authority (PoA)
blockchain. It is an ethereum-compatible blockchain which uses Byzantine
consensus to replace the original proof-of-work (PoW) from Ethereum.
Leth: Ethereum Smart Vault. Leth is permissioned blockchain protocol to
empower content creators to monetise their intellectual property data. It can
be used a CLI or HTTP server.

37. SHOWCASE Video
Presenting lightstreams tech stack in a showcase video
https://vimeo.com/322754506
Useful links
● Lightchain
● Block Explorer (sirius)
● Leth documentation
● Leth HTTP API
● Javascript Leth SDK

38. Lightstreams DApp Challenge
Description Developer a DApp using Lightstreams tech stack
Prize 500-1000 USD (in PHT)
Conditions
● Register your project request at discuss.lightstreams.network
● Deliver a running version of the project
● Documentation
● Open-source project

39. Q/A
¡ Gracias por su atención !
More questions? Email us
gabriel@lightstreams.io
lukas@lightstreams.io
Give us some feedback !!!
https://workshop.lightstreams.io