BLOCKCHAIN
@RomeoKienzler
Bitcoin
- oldest cryptocurrency
- initiated anonymously (paper + source code)
- creates a distributed ledger secured by proof of work
- proof of work SHA-256 based
- This is a problem! (see later)
Bitcoin (Blockchain)
Bitcoin (Block)
Bitcoin (Transaction)
Proof of Work
- sha256(sha265(Block + Nonce)) = Hash
- choose Nonce so that Hash starts with d leading zeros
- d depends on "difficulty" and provided by the bitcoin network
- Finding correct Nonce is "proof of work" and is rewarded with bitcoins (this is called bitcoin mining)
The problem with SHA256
The problem with SHA256
- Easy to speed up using
- GPU
- FPGA
- ASIC
- Currently without the latest ASIC you spend more on energy than earning bitcoins
What is an ASIC
- Very low cost ultra high performance chip specialized on only one task
What is an ASIC
- Very low cost ultra high performance chip specialized on only one task
What is an ASIC
- Very low cost ultra high performance chip specialized on only one task
What is an ASIC
- Very low cost ultra high performance chip specialized on only one task
What is an ASIC
- Very low cost ultra high performance chip specialized on only one task
The Problem with SHA256
- Original Idea is gone (everybody can mine bitcoins using his spare compute resources at home)
- system now vulnerable to 51% attack
- recently 50% of mining power achieved by a single pool
Alternative CryptoCurrencies
- There are many alternatives
- Auroracoin, BlackCoin, Dash, Dogecoin, DigitalNote, Ethereum, Litecoin, Mastercoin, MazaCoin, Monero, Namecoin, Nxt, Peercoin, Emercoin, PotCoin, Primecoin, Ripple, ShadowCash, Titcoin
- Alternative hash algorithms
- scrypt, X11, cryptonight, hashimoto
- Alternative consensus methods
- proof of stake
beyond payments
- Idea: BlockChain as distributed ledger to ensure non-centralized authority on validation of any type of transaction
- two promising candidates
- Ethereum (Swiss Non-Profit Organization)
- Hyperledger Project (The Linux Foundation, members: IBM, Deutsche Börse Group, Intel, JP Morgan, Cisco, RedHat, ...)
IBM Blockchain
- Service running in the IBM Cloud
- based on IBM's implementation of Hyperledger