Speaker: Andrey Krichevskiy Genre & level: Backend, Junior 2018 can perhaps be called the year of Bitcoin. But while most people have heard of Bitcoin and blockchain, few fully grasp the technology behind it. Spoiler: blockchain is NOT a magical database in the cloud, but can perhaps be considered one of the slowest distributed databases known to man. But if blockchain is the slowest distributed database known to man, why are people using it? This talk will explore the benefits and true costs of blockchain technology. You will learn why blockchain is not as flawless as we’ve been led to believe, but how the transparency that comes with it has unlocked a whole new set of possibilities. If you’d like to be inspired by possible use cases in our own landscape, then this is the talk for you!

1. Blockchain intro
1
Andrey Krichevskiy

2. 2
Ledger

3. 3
Distributed network of peers
Alice Bob
Charlie Dave
Ledger
A pays B €10
<A signature>
C pays B €5
<C signature>
D pays A € 15
<D signature>
Ledger
Ledger
Ledger
Ledger

4. Trust the ledger which has the most computational work put into it
4
Proof of work(Mining or validation)
Block of transactions
A pays B €10
<A signature>
C pays B €5
<C signature>
D pays A € 15
<D signature>
42(nonce)
Sha256
000000000000000
000000000000000
101000111000111
110000011010101…
Takes around 10 minutesProbabilty
!
"#$ =
!
!$$$$$$$$$
Hash starts with 30 zeros
Slow to calculate, but easy to verify

5. 5
Block creators(Miners). Who are they?
Alice(Miner)
Bob
Charlie Dave(miner)
block
A earns € 3
B pays A €5
<B signature>
D pays C €5
<D signature>
C pays A € 15
<C signature>
5318954

6. 6
Chain of blocks(Ordering)
prev hash
A pays B €10
<A signature>
C pays B €5
<C signature>
D pays A € 15
<D signature>
7359534
prev hash
B pays A €5
<B signature>
D pays C €5
<D signature>
C pays A € 15
<C signature>
5318954
prev hash
A pays C €15
<A signature>
C pays B €10
<C signature>
B pays D € 5
<B signature>
8079457
sha256 sha256 sha256

7. • Open for read and write for everyone
• No trust between peers -> use PoW, PoS or other consensus mechanism
• Slow transactions(minutes for one block)
• Analogy: Internet
7
Everything above was a Public(permissionless) blockchain

8. • Permissioned read/write. Access and invites are controlled by administrators
• More trust between participants
• Faster transactions
• Analogy: Intranet
8
Another breed: Federated(permissioned) blockchain

9. 9
Example

10. Thanks!
till next Spaces Summit