Blockchain: криптовалюты и не только

1.

#
Blockchain
,

2.

,
.
Proof-of-Work (
Ethereum
-
)
blockchain
2

3.

-
3

4.

~
4

5.

31
Genesis block
$
☺)
Ethereum
smart contract)
$
Dubai Blockchain Strategy
5

6.

?
-
6

7.

1)
2)
3)
4)
7

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P2P
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9

10.

-
SHA-256 (Secure Hash Algorithm)
public key)
private key)
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11.

version
version
bits
nonce
prev_block
timestamp
bits, nonce
prev_block
,
timestamp
merkle_root
txns, txn_count
merkle_root
txn_count, txns
ID_0
.
.
.
ID_M
11

12.

. Genesis block
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13.

1.
H_A = SHA256(SHA256(A))
2.
H_AB = SHA256(SHA256(H_A + H_B))
3.
H_ABCD = SHA256(SHA256(H_AB + H_CD))
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nonce
hash
target
+
fees
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15.

Difficulty, bits, targe
#414793
Difficulty
199,312,067,531.24
Bits
403014710
Hash
00000000000000000530216a17a
b1e11502720c784975dc7618f840
8df6f7c77
Bits = 403014710 = 0x18058436
0x18
0x058436
target
target = 0x058436 * 2^(8 * 0x18 - 3)
difficulty = max_target / target,
max_target = 0x1d00fff
difficulty
bits)
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16.

Difficulty, bits, targe
#414793
Difficulty
199,312,067,531.24
Bits
403014710
Hash
00000000000000000530216a17a
b1e11502720c784975dc7618f840
8df6f7c77
difficulty = 199,312,067,531.24
log2(199,312,067,531) + 32 = 69.53
Hash = 0000 0000 0000 0000 0530 216a 17ab 1e11 5027 20c7 8497
5dc7 618f 8408 df6f 7c77
0
69
Сложность создания блока в GH/s:
2^69.53 / 10 min = 1,420,000,000
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17.

:
nonce:
• Difficulty = 1
• Difficulty = 2
• Difficulty = 4
(nonce=69817)
nonce=20)
(nonce=120)
nonce
+
+
+
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18.

(2016-2018
.)
https://blockchain.info/
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19.

19

20.

Proof-of-Work
Proof-of-Work
(DoS-
-
C. Dwork, M. Naor
1997
, 1992
Hashcash (
Hash
20

21.

Proof-of-Stake
PPCoin (PeerCoi
stake
Proof-of-Work
21

22.

Proof-of-Stake
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23.

• Proof-of-Activity
• Proof-of-Burn
PoW
PoS
• Proof-of-Capacity
• Proof-of-Storage
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24.

Radeon RX Vega 56
36 MH/s
GeForce 1080 Ti
31 MH/s
Radeon R9 390X 8Gb
31 MH/s
GeForce GTX 1070 FE
27 MH/s
RX 480
24 MH/s
:
Bitcoin Mine, BTCMiner, CGMiner, BFGMiner
NVIDIA GeForce GTX 1080 Ti
AMD Radeon R9 390X 8Gb
https://whattomine.com/coins/
http://jkcrypto.com/coin-to-mine-with-nvidia-gtx-1080-ti/
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fork
Ethereum, Litecoin, Zcoin
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26.

Ethereum
$44
Bitcoin Cash
$23
IOTA
$11
Ripple
$9
Litecoin
$8
Dash
$6
https://www.rbc.ru/money/11/12/2017/5a212a1e9a79473b35558cb4
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Ethereum
Ethereum
Ethereum
!
:
-
(20-
)
Ethereum,
Ethereum Classic
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Ethereum vs Bitcoin
(
)
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-
.
-
:
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-
1.
2.
3.
4.
5.
6.
pragma solidity ^0.4.0;
contract Counter {
int private count = 0;
function incrementCounter() public {
count += 1;
}
function decrementCounter() public {
count -= 1;
}
function getCount() public constant returns
(int) {
return count;
}
}
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-
.
-
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32.

-
.
-
(slock.it)
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-
.
-
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-
.
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P.S.
КАФЕДРА ГЕОИНФОРМАТИКИ И ИНФОРМАЦИОННОЙ БЕЗОПАСНОСТИ
САМАРСКОГО УНИВЕРСИТЕТА
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