Blockchain. Manipulationssicherung von EnterpriseDatenbanken mittels öfentlicher. Blockchains. Martin Kreidenweis , Big Techday, München

Transcription

1 Blockchain Manipulationssicherung von EnterpriseDatenbanken mittels öfentlicher Blockchains Martin Kreidenweis , Big Techday, München

2 Blockchain Private Blockchains Wann Blockchain nutzen? Manipulationssicherung privater Datenbanken

3 Blockchain Was bringt uns das wirklich?

4 Abstract. A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they'll generate the longest chain and outpace attackers. The network itself requires minimal structure. Messages are broadcast on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone.

5 Abstract. A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power. As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they'll generate the longest chain and outpace attackers. The network itself requires minimal structure. Messages are broadcast on a best effort basis, and nodes can leave and rejoin the network at will, accepting the longest proof-of-work chain as proof of what happened while they were gone.

6 dezentral

7 Blockchain

8 Block n Daten Tx1 Tx2 Tx3...

9 k n 1 Block n en 1 Daten Tx2 vious Hash k Hash Tx3... Tx1 Tx2 Previous Hash Block Hash Tx3...

10 k n 1 Block n en 1 Daten Tx2 vious Hash Tx3... Tx1 Tx2 Previous Hash ce Nonce k Hash Block Hash Tx3...

11 Proof of Work

12 Proof of Work "Hello, world!0" => 1312af178c253f84028d480a6adc1e25e81caa44c749ec e2ec934c64

13 Proof of Work "Hello, world!0" => 1312af178c253f84028d480a6adc1e25e81caa44c749ec e2ec934c64 "Hello, world!1" => e9afc424b79e4f6ab42d99c81156d3a17228d6e1eef4139be78e948a9332a7d8

14 Proof of Work "Hello, world!0" => 1312af178c253f84028d480a6adc1e25e81caa44c749ec e2ec934c64 "Hello, world!1" => e9afc424b79e4f6ab42d99c81156d3a17228d6e1eef4139be78e948a9332a7d8... "Hello, world!4249" => c004190b822f1669cac8dc37e761cb73652e7832fb cf26ebb9e6 "Hello, world!4250" => 0000c3af42fc31103f1fdc0151fa747ff87349a4714df7cc52ea464e12dcd4e9

15 wahrscheinlich

16 ock 5 Blockchain Block 6 Block 7 Block 7b Block 8 Block 9

17 Konsens

18 Konsens-Modelle Proof of Work Proof of Stake Proof of Authority Signing instead of Mining

19

20 Private Blockchains

21 Blockchains for Business

22

23 Frameworks Tools

24

25 Proof of Elapsed Time

26

27 Notaries

28 Zentralisierung

29

30 Wann ist Blockchain sinnvoll?

31 Do I need a Blockchain? No. David Birch Blockchain Decision Model

32

33 Dezentralisierung Disintermediation

34 Gründe für Blockchain Notwendigkeit Zustand zu speichern Geteilter Schreibzugrif Interaktion zwischen Transaktionen Kein Vertrauen zwischen den Parteien Kein vertrauter Intermediär Marketing

35 Konnten wir das Problem auch schon vor Blockchain lösen?

36 Können wir das Problem mit Blockchain 10x besser lösen?

37

38 Manipulationssicherung privater Datenbanken mittels öfentlicher Blockchains

39 Warum?

40 Blockchain Manipulationssicherheit Datenschutz Kosten Performance Datenbank Kombination

41 Wie?

42 1. Daten Hash 2. Hash Blockchain 3. fertig

43

44 Verifzierung

45 1. Daten Hash 2. Blockchain Hash 3. Vergleich

46 OpenTimestamps

47 OpenTimestamps const detached = OpenTimestamps.DetachedTimestampFile.fromBytes(new OpenTimestamps.Ops.OpSHA256(), buffer); OpenTimestamps.stamp(detached).then(() => { const fileots = detached.serializetobytes(); });

48 Beispiel: Zeitbuchung für Freelancer

49 Beispiel: Zeitbuchung für Freelancer

50 Datenschutz

51 Daten veröfentlichen?

52 Hash-Baum Merkle-Tree

53 Hash Kunde 1 Kunde 2 Kunde 3 Kunde 4

54 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 3 Kunde 4

55 Hash 0 Hash 1 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 3 Kunde 4

56 Root Hash Hash 0 Hash 1 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 3 Kunde 4

57 Root Hash Hash 0 Hash 1 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 3 Kunde 4

58 Root Hash Hash 0 Hash 1 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 3 Kunde 4

59 Root Hash Hash 0 Hash 1 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 3 Kunde 4

60 Datenschutz

61 Root Hash Hash 0 Hash 1 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 2b Kunde 3

62 Root Hash Hash 0 Hash 1 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 2b Kunde 3

63 Root Hash Hash 0 Hash 1 Hash 0-0 Hash 0-1 Hash 1-0 Hash 1-1 Kunde 1 Kunde 2 Kunde 2b Kunde 3

64 Existenzbeweis

65 Kein Beweis der Nicht-Existenz

66 Ein Ort für die gesamte Wahrheit

67

68 Smart Contracts

69 Smart Contracts

70 World Computer

71

72 ERC20 Token Standard

73

74 Smart Contracts

75 Oracles Photo by Jamie Street on Unsplash

76 Ein Ort für die gesamte Wahrheit

77 contract HashStore is owned { mapping(uint256 => bytes32) public storedhashes; } function storehash(uint256 stakeholderid, bytes32 hash) owneronly external { storedhashes[stakeholderid] = hash; }

78 Beweis der Nicht-Existenz

79 Jeder Zustand des Systems

80 Versionierung

81 Append-Only

82 Event Sourcing

83 LineItem Item Line Order Shipping Info

84 LineItem Item Line Order Shipping Info Cart Created Item Added Item Added Item Added Item Removed Shipping Info Added t

85 Event 1 Event 2 Event 3 Daten Daten Daten Previous Hash Previous Hash Event Hash Event Hash Event Hash

86 Jeder Zustand des Systems

87 Event Stream

88 Event Stream Event Stream

89 Event Stream Hash Event Stream Hash Event Stream

90 Event Stream Hash Event Stream Hash Event Stream

91 Encoding

92 Signaturen

93 GDPR

94