Ethereum: Smart Contracts & Varianten

https://software-architecture-summit.de/softwarearchitektur/blockchain-crypto-waehrungen-und-plattformen/

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1. E t h e r e u m : S m a r t C o n t r a c t s & V a r i a n t e n L a r s H u p e l S o f t w a r e A r c h i t e c t u r e S u m m i t 2 0 1 9 - 0 3 - 1 2
2. E t h e r e u m • e i n e d e r j ü n g e r e n B l o c k c h a i n s • W ä h r u n g : E t h e r ( E T H ) • P l a t z 2 – 3 i n M a r k t k a p i t a l i s i e r u n g • t e c h n i s c h e N e u e r u n g : P l a t t f o r m f ü r D e c e n t r a l i z e d A p p s
3. D e c e n t r a l i z e d A p p s
4. E t h e r e u m Z w e i A r t e n v o n A c c o u n t s : 1 . E x t e r n a l l y O w n e d 2 . S m a r t C o n t r a c t s
5. S m a r t C o n t r a c t s
6. S m a r t C o n t r a c t s . . . s i n d s p e z i e l l e A c c o u n t s m i t e i g e n e r I d e n t i t ä t u n d K o n t o s t a n d
7. S m a r t C o n t r a c t s . . . s i n d s p e z i e l l e A c c o u n t s m i t e i g e n e r I d e n t i t ä t u n d K o n t o s t a n d . . . h a b e n k e i n e O w n e r s h i p
8. S m a r t C o n t r a c t s . . . s i n d s p e z i e l l e A c c o u n t s m i t e i g e n e r I d e n t i t ä t u n d K o n t o s t a n d . . . h a b e n k e i n e O w n e r s h i p . . . e n t h a l t e n S p e i c h e r z e l l e n m i t v e r ä n d e r l i c h e n W e r t e n
9. S m a r t C o n t r a c t s . . . s i n d s p e z i e l l e A c c o u n t s m i t e i g e n e r I d e n t i t ä t u n d K o n t o s t a n d . . . h a b e n k e i n e O w n e r s h i p . . . e n t h a l t e n S p e i c h e r z e l l e n m i t v e r ä n d e r l i c h e n W e r t e n . . . b e s t e h e n a u s u n v e r ä n d e r l i c h e m C o d e
10. S m a r t C o n t r a c t s . . . s i n d s p e z i e l l e A c c o u n t s m i t e i g e n e r I d e n t i t ä t u n d K o n t o s t a n d . . . h a b e n k e i n e O w n e r s h i p . . . e n t h a l t e n S p e i c h e r z e l l e n m i t v e r ä n d e r l i c h e n W e r t e n . . . b e s t e h e n a u s u n v e r ä n d e r l i c h e m C o d e . . . k ö n n e n m i t a n d e r e n C o n t r a c t s i n t e r a g i e r e n , w e r d e n a b e r n i e s e l b s t s t ä n d i g a k t i v
11. V e r g l e i c h : d i g i t a l e r N o t a r • R e c h t e u n d P f l i c h t e n v e r t r a g l i c h f e s t g e l e g t • n e u t r a l e I n s t a n z ü b e r w a c h t A b l a u f • I n t e r a k t i o n m i t d r i t t e n P a r t e i e n
12. T r a n s a k t i o n s a r t e n P a y m e n t Ü b e r t r a g v o n G e l d i n e i n e n C o n t r a c t o d e r E O A C a l l A u f r u f e i n e r F u n k t i o n I n t e r n a l C o n t r a c t i n t e r a g i e r t m i t a n d e r e m C o n t r a c t
14. E t h e r e u m V i r t u a l M a c h i n e
15. V i r t u e l l e M a s c h i n e n s i n d M i s c h f o r m e n z w i s c h e n I n t e r p r e t e r u n d C o m p i l e r
16. A b l a u f e i n e r T r a n s a k t i o n
17. A b l a u f e i n e r T r a n s a k t i o n 1 . U s e r e r z e u g t T r a n s a k t i o n : S i g n a t u r ( e n t h ä l t Q u e l l e ) Z i e l G e l d b e t r a g D a t e n
18. A b l a u f e i n e r T r a n s a k t i o n 1 . U s e r e r z e u g t T r a n s a k t i o n : S i g n a t u r ( e n t h ä l t Q u e l l e ) Z i e l G e l d b e t r a g D a t e n 2 . M i n e r ü b e r p r ü f e n G ü l t i g k e i t
19. A b l a u f e i n e r T r a n s a k t i o n 1 . U s e r e r z e u g t T r a n s a k t i o n : S i g n a t u r ( e n t h ä l t Q u e l l e ) Z i e l G e l d b e t r a g D a t e n 2 . M i n e r ü b e r p r ü f e n G ü l t i g k e i t 3 . M i n e r f ü h r e n C o d e a u s , f a l l s Z i e l e i n C o n t r a c t i s t
20. A b l a u f e i n e r T r a n s a k t i o n 1 . U s e r e r z e u g t T r a n s a k t i o n : S i g n a t u r ( e n t h ä l t Q u e l l e ) Z i e l G e l d b e t r a g D a t e n 2 . M i n e r ü b e r p r ü f e n G ü l t i g k e i t 3 . M i n e r f ü h r e n C o d e a u s , f a l l s Z i e l e i n C o n t r a c t i s t 4 . P e r s i s t i e r e n d e r Ä n d e r u n g e n i n d i e B l o c k c h a i n
21. interface Transaction { // signature: contains public key of EOA Signature getSignature(); // recipient address, can be any address type Address getRecipient(); // amount of Ether to be sent, can be 0 Value getValue(); // data for a call, can be empty String getData(); // internal TXNs List<Transaction> getInternalTxns(); }
23. W a s k a n n d i e E V M ? 1 . a r i t h m e t i s c h e O p e r a t i o n e n 2 . b i t w e i s e & l o g i s c h e O p e r a t i o n e n 3 . H a s h e s ( m e i s t S H A - 3 ) 4 . U m g e b u n g s i n f o r m a t i o n ( K o n t o s t a n d , A u f r u f e r , . . . ) 5 . B l o c k i n f o r m a t i o n ( Z e i t s t e m p e l , B l o c k n u m m e r , . . . ) 6 . S t a c k - u n d S p e i c h e r o p e r a t i o n e n 7 . S p r ü n g e 8 . L o g g i n g 9 . K o n t o o p e r a t i o n e n ( E r z e u g u n g , Z a h l u n g , A u f r u f , . . . )
26. • S m a r t C o n t r a c t s w e r d e n v o n a l l e n M i n e r n a u s g e f ü h r t
27. • S m a r t C o n t r a c t s w e r d e n v o n a l l e n M i n e r n a u s g e f ü h r t • B e r e c h n u n g d e r T r a n s a k t i o n s g e b ü h r a n h a n d d e r A u s f ü h r u n g s d a u e r
28. • S m a r t C o n t r a c t s w e r d e n v o n a l l e n M i n e r n a u s g e f ü h r t • B e r e c h n u n g d e r T r a n s a k t i o n s g e b ü h r a n h a n d d e r A u s f ü h r u n g s d a u e r • U s e r m u s s e i n e T a n k g r ö ß e u n d e i n e n S p r i t p r e i s a n g e b e n
29. • S m a r t C o n t r a c t s w e r d e n v o n a l l e n M i n e r n a u s g e f ü h r t • B e r e c h n u n g d e r T r a n s a k t i o n s g e b ü h r a n h a n d d e r A u s f ü h r u n g s d a u e r • U s e r m u s s e i n e T a n k g r ö ß e u n d e i n e n S p r i t p r e i s a n g e b e n • j e d e O p e r a t i o n h a t e i n e n d e f i n i e r t e n V e r b r a u c h
31. P r o g r a m m i e r u n g & T o o l s
32. E i n e i n f a c h e r C o n t r a c t 608060405234801561001057600080fd5b506000808190555033600160006101000a81548173ffff ffffffffffffffffffffffffffffffffffff021916908373ffffffffffffffffffffffffffffffff ffffffff1602179055506101be806100686000396000f30060806040526004361061004c57600035 7c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063 3ccfd60b146100515780638f9595d414610068575b600080fd5b34801561005d57600080fd5b5061 0066610086565b005b61007061011d565b6040518082815260200191505060405180910390f35b60 0160009054906101000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffffff ffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffffffffffffffffff1614 15156100e257600080fd5b600160009054906101000a900473ffffffffffffffffffffffffffffff ffffffffff1673ffffffffffffffffffffffffffffffffffffffff16ff5b60006001600090549061 01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffff ffffffffffffffff163373ffffffffffffffffffffffffffffffffffffffff1614151561017b5760 0080fd5b3460008082825401925050819055506000549050905600a165627a7a72305820b4d2d5a2 acfa0e197908c7c57826d35a987f64b29f8b97020a4ca96f63ce66630029
33. E i n e i n f a c h e r C o n t r a c t 608060405234801561001057600080fd5b506000808190555033600160006101000a81548173ffff ffffffffffffffffffffffffffffffffffff021916908373ffffffffffffffffffffffffffffffff ffffffff1602179055506101be806100686000396000f30060806040526004361061004c57600035 7c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063 3ccfd60b146100515780638f9595d414610068575b600080fd5b34801561005d57600080fd5b5061 0066610086565b005b61007061011d565b6040518082815260200191505060405180910390f35b60 0160009054906101000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffffff ffffffffffffffffffffffffffffff163373ffffffffffffffffffffffffffffffffffffffff1614 15156100e257600080fd5b600160009054906101000a900473ffffffffffffffffffffffffffffff ffffffffff1673ffffffffffffffffffffffffffffffffffffffff16ff5b60006001600090549061 01000a900473ffffffffffffffffffffffffffffffffffffffff1673ffffffffffffffffffffffff ffffffffffffffff163373ffffffffffffffffffffffffffffffffffffffff1614151561017b5760 0080fd5b3460008082825401925050819055506000549050905600a165627a7a72305820b4d2d5a2 acfa0e197908c7c57826d35a987f64b29f8b97020a4ca96f63ce66630029
34. S o l i d i t y • p o p u l ä r s t e H o c h s p r a c h e f ü r E V M - B y t e c o d e • g e t y p t , o b j e k t o r i e n t i e r t • s y n t a k t i s c h a n J a v a s c r i p t a n g e l e h n t
35. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
36. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
37. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
38. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
39. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
40. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
41. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
42. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
43. pragma solidity ^0.4.22; contract Wallet { uint256 balance; address owner; constructor () public { balance = 0; owner = msg.sender; } function addfund() payable public returns (uint256) { require (msg.sender == owner); balance += msg.value; return balance; } function withdraw() public { require (msg.sender == owner); selfdestruct(owner); } }
44. w e b 3 . j s • o f f i c i a l J a v a S c r i p t A P I f o r E t h e r e u m • a v a i l a b l e f o r t h e b r o w s e r a n d N o d e . j s
45. w e b 3 . j s var contract = new web3.eth.Contract( abi, {data: codeHex, from: web3.eth.defaultAccount }); var deployTransaction = contract.deploy({data: codeHex, arguments: []}); web3.eth.personal.unlockAccount(web3.eth.defaultAccount, "user") .then(() => deployTransaction.estimateGas()) .then(gas => deployTransaction.send({gasLimit: gas, from: web3.eth.defaultAccount})) .then(contract => console.log("Address of new contract: " + contract.options.address)) .catch(err => console.log(err));
46. M e t a m a s k • B r o w s e r - P l u g i n z u r V e r w a l t u n g v o n E t h e r e u m - A d r e s s e n • k o m m u n z i e r t ü b e r R P C m i t B l o c k c h a i n - K n o t e n • i n t e g r i e r t m i t w e b 3 . j s
50. B e i s p i e l e
51. B e i s p i e l e
52. B e i s p i e l e • M u l t i - S i g n a t u r - W a l l e t s
53. B e i s p i e l e • M u l t i - S i g n a t u r - W a l l e t s • E R C - 2 0 - T o k e n
54. B e i s p i e l e • M u l t i - S i g n a t u r - W a l l e t s • E R C - 2 0 - T o k e n • H a n d e l s b ö r s e n
55. B e i s p i e l e • M u l t i - S i g n a t u r - W a l l e t s • E R C - 2 0 - T o k e n • H a n d e l s b ö r s e n • W e t t e n
56. B e i s p i e l e • M u l t i - S i g n a t u r - W a l l e t s • E R C - 2 0 - T o k e n • H a n d e l s b ö r s e n • W e t t e n • C r y p t o k i t t i e s
57. K o m p o n e n t e n e i n e r D a p p • W e b a p p l i k a t i o n m i t J S ( m e i s t o p e n s o u r c e ) • S m a r t C o n t r a c t ( s ) • B l o c k c h a i n
58. S o f t w a r e q u a l i t ä t
59. E n t w i c k l u n g s - W o r k f l o w
60. E n t w i c k l u n g s - W o r k f l o w 1 . C o n t r a c t i n S o l i d i t y e n t w i c k e l n
61. E n t w i c k l u n g s - W o r k f l o w 1 . C o n t r a c t i n S o l i d i t y e n t w i c k e l n 2 . m i t R e m i x / M e t a m a s k a u s r o l l e n
62. E n t w i c k l u n g s - W o r k f l o w 1 . C o n t r a c t i n S o l i d i t y e n t w i c k e l n 2 . m i t R e m i x / M e t a m a s k a u s r o l l e n 3 . ? ? ?
63. • S m a r t C o n t r a c t s s i n d u n v e r ä n d e r l i c h
64. • S m a r t C o n t r a c t s s i n d u n v e r ä n d e r l i c h • T r a n s a k t i o n e n s i n d e n d g ü l t i g
65. • S m a r t C o n t r a c t s s i n d u n v e r ä n d e r l i c h • T r a n s a k t i o n e n s i n d e n d g ü l t i g • e s g i b t k e i n e K o n t r o l l i n s t a n z *
66. • S m a r t C o n t r a c t s s i n d u n v e r ä n d e r l i c h • T r a n s a k t i o n e n s i n d e n d g ü l t i g • e s g i b t k e i n e K o n t r o l l i n s t a n z * • F e h l e r s i n d n i c h t k o r r i g i e r b a r *
67. F a t a l e F e h l e r T h e D A O ( 2 0 1 6 ) • D e c e n t r a l i z e d A u t o n o m o u s O r g a n i z a t i o n • e i n e A r t d i g i t a l e r G e b e r v o n W a g n i s k a p i t a l • I d e e : I n v e s t o r * i n n e n s t i m m e n ü b e r K a p i t a l n u t z u n g a b • B u g i m C o n t r a c t f ü h r t e z u m A b g r e i f e n v o n 5 0 M i l l i o n e n U S D
68. F a t a l e F e h l e r P a r i t y W a l l e t ( 2 0 1 7 ) • O n l i n e W a l l e t f ü r E t h e r u n d a n d e r e T o k e n • B u g i m C o n t r a c t f ü h r t e z u m A b g r e i f e n v o n 3 0 M i l l i o n e n U S D
69. F a t a l e F e h l e r P a r i t y W a l l e t ( 2 0 1 7 ) • O n l i n e W a l l e t f ü r E t h e r u n d a n d e r e T o k e n • B u g i m C o n t r a c t f ü h r t e z u m A b g r e i f e n v o n 3 0 M i l l i o n e n U S D • w e i t e r e r B u g f ü h r t e z u m T o t a l v e r l u s t v o n 3 6 0 M i l l i o n e n U S D
70. Q u a l i t ä t s s i c h e r u n g T r u f f l e : F r a m e w o r k f ü r d e n g e s a m t e n E n t w i c k l u n g s z y k l u s • T e s t i n g ( S o l i d i t y u n d J a v a S c r i p t ) • D e p l o y m e n t • M i g r a t i o n s
71. C o d e i s L a w “ H o w e v e r , t h e s e m o r e c o m p l e x a g r e e m e n t s , w i t h g r e a t e r e n g a g e m e n t w i t h r e a l w o r l d g o o d s a n d s e r v i c e s , h i g h l i g h t t h e n e c e s s i t y o f e f f e c t i v e d i s p u t e r e s o l u t i o n , a s w e l l a s i n d i c a t e a n e c e s s a r y i n t e r r e l a t i o n w i t h t e r r i t o r i a l l e g a l s y s t e m s .
72. C o d e i s L a w “ H o w e v e r , t h e s e m o r e c o m p l e x a g r e e m e n t s , w i t h g r e a t e r e n g a g e m e n t w i t h r e a l w o r l d g o o d s a n d s e r v i c e s , h i g h l i g h t t h e n e c e s s i t y o f e f f e c t i v e d i s p u t e r e s o l u t i o n , a s w e l l a s i n d i c a t e a n e c e s s a r y i n t e r r e l a t i o n w i t h t e r r i t o r i a l l e g a l s y s t e m s . C o n t e s t a t i o n m e c h a n i s m s a r e n e c e s s a r y t o ‘ s o f t e n ’ t h e e f f e c t s o f s e l f - e x e c u t i n g ‘ s m a r t c o n t r a c t s ’, a n d m a k e t r a n s a c t i o n s r e v e r s i b l e , a l l o w - i n g t h e o u t c o m e s o f d i s p u t e r e s o l u t i o n t o b e e n f o r c e d . ” G o l d e n f e i n & L a t e r : “ L e g a l E n g i n e e r i n g o n t h e B l o c k c h a i n : ‘ S m a r t C o n t r a c t s ’ a s L e g a l C o n d u c t ” ( 2 0 1 8 )
73. H ü r d e n f ü r S m a r t C o n t r a c t s • b i s h e r k e i n e e t a b l i e r t e n f o r m a l e n M e t h o d e n • u n k l a r e J u r i s d i k t i o n • N a c h v o l l z i e h b a r k e i t d e s C o d e s
74. V a r i a n t e n v o n E t h e r e u m
75. E t h e r e u m C l a s s i c • H a r d F o r k i m J u l i 2 0 1 6 • U r s a c h e : U n s t i m m i g k e i t ü b e r V o r g e h e n n a c h D A O - H a c k • P l a t z 1 8 i n M a r k t k a p i t a l i s i e r u n g
76. P r o o f o f W o r k • e i n g e f ü h r t d u r c h B i t c o i n • R ü c k g r a t d e r m e i s t e n K r y p t o w ä h r u n g e n • b a s i e r t a u f I n v e s t i t i o n v o n S t r o m
77. P r o o f o f S t a k e • e x p e r i m e n t e l l e ( s ) V e r f a h r e n • b a s i e r t a u f A b s t i m m u n g ü b e r B l ö c k e • G e w i c h t u n g n a c h S t a k e : z . B . V e r m ö g e n o d e r V e r m ö g e n s a l t e r • a l s Z i e l f ü r E t h e r e u m v o r g e s e h e n • U m s e t z u n g u n k l a r
78. P r o o f o f A u t h o r i t y • e i n K o n s o r t i u m e i n i g t s i c h ü b e r v e r t r a u e n s w ü r d i g e K n o t e n • a b w e c h s e l n d e E r z e u g u n g v o n B l ö c k e n • k e i n e T r a n s a k t i o n s g e b ü h r n ö t i g • K o n s o r t i u m k a n n s e l b s t ü b e r S m a r t C o n t r a c t g e s t e u e r t w e r d e n
80. R u s t & W e b A s s e m b l y
81. R u s t & W e b A s s e m b l y R u s t • m a s c h i n e n n a h e S p r a c h e v o n M o z i l l a • F o k u s a u f S p e i c h e r s i c h e r h e i t • k e i n G C � W e b A s s e m b l y • A s s e m b l e r s p r a c h e f ü r d e n B r o w s e r • l ä u f t i n d e r J S - S a n d b o x • k e i n Z u g r i f f a u f d e n D O M
82. E W A S M • W e b A s s e m b l y a u f d e r E V M : v i e l v e r s p r e c h e n d e E n t w i c k l u n g • d e r z e i t n o c h u n s p e z i f i z i e r t • e x p e r i m e n t e l l e I m p l e m e n t i e r u n g i n P a r i t y
83. #[eth_abi(CAEndpoint, CAClient)] pub trait CAInterface { fn constructor(&mut self); #[constant] fn owner(&mut self) -> U256; } pub struct CAContract; impl CAInterface for CAContract { fn constructor(&mut self) { OWNER.write_as(pwasm_ethereum::sender()); } fn owner(&mut self) -> U256 { OWNER.read_as() } }
84. F a z i t
85. F a z i t • E t h e r e u m i s t b i s h e r g r ö ß t e P l a t t f o r m f ü r D a p p s • h o h e E n t w i c k l u n g s g e s c h w i n d i g k e i t • l e i d e t a n m a n g e l h a f t e m S p r a c h d e s i g n • P r o o f o f A u t h o r i t y u n d E W A S M v i e l v e r s p r e c h e n d , a b e r n o c h i n d e n K i n d e r s c h u h e n
86. Q & A L a r s H u p e l � l a r s . h u p e l @ i n n o q . c o m � @ l a r s r _ h w w w . i n n o q . c o m i n n o Q D e u t s c h l a n d G m b H K r i s c h e r s t r . 1 0 0 4 0 7 8 9 M o n h e i m a . R h . G e r m a n y + 4 9 2 1 7 3 3 3 6 6 - 0 O h l a u e r S t r . 4 3 1 0 9 9 9 B e r l i n G e r m a n y L u d w i g s t r . 1 8 0 E 6 3 0 6 7 O f f e n b a c h G e r m a n y K r e u z s t r . 1 6 8 0 3 3 1 M ü n c h e n G e r m a n y c / o W e W o r k H e r m a n n s t r a s s e 1 3 2 0 0 9 5 H a m b u r g G e r m a n y i n n o Q S c h w e i z G m b H G e w e r b e s t r . 1 1 C H - 6 3 3 0 C h a m S w i t z e r l a n d + 4 1 4 1 7 4 3 0 1 1 1 A l b u l a s t r . 5 5 8 0 4 8 Z ü r i c h S w i t z e r l a n d
87. L A R S H U P E L C o n s u l t a n t i n n o Q D e u t s c h l a n d G m b H L a r s e n j o y s p r o g r a m m i n g i n a v a r i e t y o f l a n - g u a g e s , i n c l u d i n g S c a l a , H a s k e l l , a n d R u s t . H e i s k n o w n a s a f r e q u e n t c o n f e r e n c e s p e a k e r a n d o n e o f t h e f o u n d e r s o f t h e T y p e l e v e l i n i t i a t i v e w h i c h i s d e d i c a t e d t o p r o v i d i n g p r i n c i p l e d , t y p e - d r i v e n S c a l a l i b r a r i e s .
88. B i l d q u e l l e n D e c e n t r a l i z e d A p p s : https: //medium.com/swlh/understanding-dapps- decentralized-applications-8f3668ebdc9a S m a r t C o n t r a c t : http://instaco.de/, https://www.ethereum.org/token A k t e n : https://pixabay.com/photos/files- ddr-archive-1633406/ E t h e r e u m T r a n s a c t i o n s : https://medium.com/@preethikasireddy/how- does-ethereum-work-anyway-22d1df506369 P l a t i n e : https://commons.wikimedia.org/wiki/File: Computer_Circuit_Board_MOD_45153619.jpg, H a r l a n d Q u a r r i n g t o n , O G L 1 . 0 G a s P u m p : https://commons.wikimedia.org/wiki/File: Antique_yard_vintage_gas_pumps,_Washington_ LCCN2010630650.tif, L i b r a r y o f C o n g r e s s T r e a t y o f R o m e : https://en.wikipedia.org/wiki/File: Treaty_of_Rome.jpg, a u t h o r u n k n o w n S c a r e d c a t : https://pixabay.com/vectors/cat-scared- hunched-spooky-black-30788/ C o i n s : https://pixabay.com/photos/money- coins-euro-coins-currency-515058/ M a c a r o o n s : https://pixabay.com/photos/macaroon- dessert-sweet-bakery-food-2815075/ P o w e r s t a t i o n : https://pixabay.com/photos/power-station- energy-electricity-374097/ U N G e n e r a l A s s e m b l y : https://www.flickr. com/photos/50371131@N04/29192350713, G o b i e r n o d e C h i l e , C C - B Y B u n d e s v e r w a l t u n g s g e r i c h t : https://pixabay.com/photos/supreme- administrative-court-court-3687414/ R a t i f i k a t i o n d e s G r u n d g e s e t z e s : https: //de.wikipedia.org/w/index.php?title=Datei: Grundgesetz_Ratifikationsunterschriften. jpg&filetimestamp=20110526174813& N Y S E : https://pixabay.com/photos/stock- exchange-trading-floor-738671/ P o k e r c h i p s : https://pixabay.com/photos/chips-play- poker-casino-gambling-2038348/ C o n t r a c t U M L : https://github.com/Azure- Samples/blockchain/blob/master/ledger/ template/ethereum-on-azure/permissioning- contracts/validation-set/media/contract- uml.png S e r v e r r a c k : https://pixabay.com/photos/server-cloud- development-business-1235959/ L i g h t n i n g : https://pixabay.com/photos/lightning-storm- weather-sky-399853/ F e r r i s t h e C r a b : https://www.rust-lang.org/what/wasm, M I T C o n s t r u c t i o n s i t e : https://pixabay.com/photos/building- construction-site-cranes-768815/ R a i l r o a d : https://pixabay.com/photos/track- railway-line-rail-traffic-3670209/