Blockchain - Sicherheit auch ohne Trust Center

1. 00:00Before we look at the blockchain technology and the individual ingredients, let us briefly to look at the Blockchain story.
2. 00:09Blockchain in the media - a permanent topic.
3. 00:13A permanent topic in the trade media, in very different areas of application, originally driven around the Bitcoin,
4. 00:22and the fantasies that came out of those courses are evolving, but very quickly the deployment scenarios,
5. 00:31how to blockchain in areas such as government, in the area of trade - Alibaba, Amazon -, in the field of energy technology, in the field of the oil industry,
6. 00:44there was no area where ideas weren't developed, how these blockchain technologies can also be used there.
7. 00:53And all of this, of course, driven by the original application. the blockchain technology, namely the Bitcoins.
8. 01:01And this crypto currency, then there was also much about the speculations, that were possible there with this currency, with these very rapid price rises, then falls again,
9. 01:15that of course has this hype about blockchain technologies, that underlie the Bitcoins.
10. 01:23What was the basic idea behind Bitcoin?
11. 01:25The basic idea of Bitcoin was, that values, amounts of money, no middlemen, can be exchanged without a bank.
12. 01:36As we know it from life, if we go anywhere Pay at the store, pay cash, or at the gas station.
13. 01:42or when we communicate with others through our bank. and transfer money there or get it yourself,
14. 01:52so the idea was whether to not use this what is possible there in the cash range - there's no bank between the money donor and the money recipient - if you can't get that in the area of the network.
15. 02:06And the big question is, if there in such a network. amounts are transferred back and forth,
16. 02:14how do you know whoever's sending me money has the money in the first place.
17. 02:20That he wouldn't spend his money more than once, transfer it to me, I don't even know who he is.
18. 02:27And there's also - as in the case of the bank - no one there, checking to see if whoever's sending money there has any of that money at all.
19. 02:37So that will be an issue, which also helps quite centrally, to explain what the problem is, achieved with blockchain technology,
20. 02:47that's that bank that's in the middle of it. in this payment transaction, she keeps records.
21. 02:53In its accounts book, the book shall record each transfer, and she knows the balance of every participant's account,
22. 03:03and if someone's trying to transfer something, without the money being in his account,
23. 03:08then the bank won't make the transfer.
24. 03:11So the bank with its accounting book has full control and see what the customers are doing.
25. 03:19It has no influence over the amount, the customer himself, of course, but she turns herself on, when money is to be transferred, which is not available at all.
26. 03:31Anyone who has an account with a bank, trusts this bank.
27. 03:36He leaves this control to the bank and says, If the bank stops this, then it's correct, without being able to verify that in detail now,
28. 03:49because the individual bank customer does not have any insight into this ledger and into the account balances of the others.
29. 03:55The idea now with the Bitcoin is, to take this bank out of play.
30. 04:02There were also historical reasons for this, namely the banking crisis at the time, where confidence in banks was shaken,
31. 04:10and the blockchain technology now offers the possibility, to replace this confidence in the bank with confidence-building algorithms.
32. 04:22So the bank in the relationship, paying, is replaced at Bitcoin by mechanisms, namely the blockchain mechanisms,
33. 04:34so that the participants in this transfer can be secure, that there's no double spending, that if someone pays, he's really capable of paying.
34. 04:48And of course this does not only apply to the traffic of two participants, but from such a whole network of customers (unv. #00:04:57-6# )
35. 04:56In the case of Bitcoin, these are the worldwide participants and users of this crypto currency.
36. 05:02By the way, crypto currency, from cryptography, because these blockchain technologies are, of course, essentially cryptographic techniques.
37. 05:12So, if these participants in the system no longer have a central anchor of trust, no bank that has the ledger,
38. 05:21then mechanisms need to be developed, mechanisms that participants are safe,
39. 05:27the state of this system, this monetary system, without being able to trust every single other participant.
40. 05:40You typically don't even know them.
41. 05:42You can join in, you can buy Bitcoins, and then you're in the game without knowing it, which participant is trustworthy and how.
42. 05:52That is what this unification process is about, but we are also talking about Consensus algorithms, they're supposed to handle it.
43. 06:00So they're supposed to coordinate all the participants, so everyone can be sure that when they receive a Bitcoin referral, that he can then actually have these bitcoins at his disposal,
44. 06:14that it is not possible to transfer such Bitcoins, when there are no Bitcoins in possession.
45. 06:22That's what's happening here, is that the blockchain offers a technique,
46. 06:27Bitcoin's basic idea was to establish a currency, without offering a bank that all participants in this financial system trust.
47. 06:41These are essentially the mechanisms, that are there to establish trust in such networks of participants, who at first don't trust each other, who don't even know each other.
48. 06:55There's no confidence building yet, i.e. establishing trust in a trustless environment.
49. 07:01So this was the first application of blockchain technology. Because that was in the currency area,
50. 07:08which in particular naturally particularly well fits the mechanisms of blockchain technology, it has reached a very high level of publicity.
51. 07:18The speculation in the currency has let the fantasies grow.
52. 07:22And the blockchain technology itself, that's the technology, who, with these cryptographic means, reached this settlement,
53. 07:31this consensus between unknown participants in such a trustless environment.
54. 07:37And technically we talk about such networks, where there's no master, no central trust anchor, of peer-to-peer networks.
55. 07:48And the peers, they're the participants in the system, they don't know each other, and blockchain technology creates the possibility
56. 08:01to build consensus among all these participants, between all those peers on such a network.
57. 08:09Now I had already said crypto currency, so these are the cryptographic techniques with which this confidence-building unification process works.
58. 08:17And we have already dealt with a bit, namely in our openHPI workshop on "Data Security on the Net".
59. 08:24There we got to know asymmetric cryptography. it was this cryptography where each participant had two keys,
60. 08:33which was a public key he shared with the whole world, and a private key he kept for himself.
61. 08:38We were able to use that asymmetric cryptography Design authentication processes,
62. 08:45we have been able to undeniably enhance the integrity of actions in a system, - that's another important pillar of blockchain technology.
63. 08:58We had discussed cryptographic hash functions in the course, those were the functions we used to maintain the integrity of messages could reach in this context the digital signature.
64. 09:13So it's all gonna play a role in this blockchain technology, because that's just a successful combination. of various security techniques, all of which were already there.
65. 09:26So that's how blockchain technology works. not an invention of new security technology,
66. 09:33but the blockchain technology is an ingenious combination of methods from asymmetric cryptography,
67. 09:42from the cryptographic hash functions and by consensus algorithms that contributed to this success in the Bitcoin system, has led to this great popularity.
68. 09:54And has stimulated the imagination that with this thought one can Trust with the help of cryptography, mathematical algorithms, to be able to establish itself in trustless environments,
69. 10:07which then radiated into these many areas of application and you've thought about it there, you can't use it there.
70. 10:15And, of course, this trustless environment through our online world.
71. 10:22The individual participants have access to the network, without knowing each other,
72. 10:28and yet, at Bitcoin, it's the financial exchange, in other applications there are other topics,
73. 10:35in such a peer-to-peer network things should be realized in a trustworthy way, without the participants trusting each other.
74. 10:47Blockchain technology achieves this.

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