Plutus and Extended UTxO

VIDEO: https://www.youtube.com/watch?v=TFezjgwuw8Y

This presentation was part of PlutusFest 2018 and introduces the design and architecture of the Plutus Platform, a Haskell-based environment and toolchain for developing contracts for the Cardano blockchain. The key features are its use of a standard purely functional programming language (instead of inventing a new language, which appears to be the popular approach), being based on a ledger-architecture that resembles a functional data flow graph (UTxO ledger, rather than an account-based ledger), and its tight integration and co-development of on-chain code (executed by block producing nodes) and off-chain code (executed on client machines).

See https://testnet.iohkdev.io/plutus/ for an online environment to write and test Plutus code and https://github.com/input-output-hk/plutus/ for the code.

Transcript

1. PLUTUS Plutus and Extended UTxO Manuel M T Chakravarty, Language Architect @ IOHK
2. PLUTUS What is Plutus?
3. PLUTUS What is Plutus? Innovative development and execution platform for distributed contract applications on Cardano SL & CL.
4. PLUTUS The Three Pillars of Plutus
5. PLUTUS Safety & Security
6. PLUTUS Safety & Security Superior Ledger
7. PLUTUS Safety & Security Superior Ledger Full Stack
8. PLUTUS Safety & Security Superior Ledger Full Stack
9. PLUTUS
10. functional programming PLUTUS λ
11. functional programming with modern type systems PLUTUS λτ
12. functional programming modern type systems PLUTUS
13. functional programming modern type systems PLUTUS input output
14. functional programming modern type systems PLUTUS input output pure function side effects
15. functional programming modern type systems PLUTUS input output typed function safe usage :: ⍺ :: β
16. PLUTUS input output typed function safe usage :: ⍺ :: β local reasoning
17. PLUTUS input output typed function safe usage :: ⍺ :: β local reasoning type-directed design
18. PLUTUS input output typed function safe usage :: ⍺ :: β local reasoning type-directed design advanced testing & verification
19. PLUTUS local reasoning type-directed design advanced testing & verification }
20. PLUTUS local reasoning type-directed design advanced testing & verification } understand code behaviour
21. PLUTUS local reasoning type-directed design advanced testing & verification } understand code behaviour find exploits
22. PLUTUS core Plutus Core
23. PLUTUS core Plutus Core not a bytecode typed FP calculus
24. PLUTUS core Plutus Core not a bytecode not a classic virtual machine typed FP calculus abstract machine interpreter
25. PLUTUS core Plutus Core small, powerful & based on peer-reviewed science not a bytecode not a classic virtual machine typed FP calculus abstract machine interpreter
26. PLUTUS core Plutus Core
27. PLUTUS core Plutus Core Where is it used?
28. PLUTUS Safety & Security Superior Ledger Full Stack
29. PLUTUS Account-based Ledger UTxO-based Ledger
30. PLUTUS Account-based Ledger UTxO-based Ledger functional imperative
31. PLUTUS Account-based Ledger UTxO-based Ledger functional imperative mutable shared state dataflow
32. PLUTUS Account-based Ledger UTxO-based Ledger functional imperative mutable shared state dataflow compositional entangled
33. PLUTUS What about the expressiveness of smart contracts?
34. PLUTUS What about the expressiveness of smart contracts? Bitcoin
35. PLUTUS What about the expressiveness of smart contracts? Bitcoin Ethereum
36. PLUTUS What about the expressiveness of smart contracts? Bitcoin Ethereum minimal
37. PLUTUS What about the expressiveness of smart contracts? Bitcoin Ethereum minimal enough rope
38. PLUTUS
39. PLUTUS
40. PLUTUS Input Output
41. PLUTUS Input Output
42. PLUTUS Input Output ν: Validator x: Value core
43. PLUTUS Input Output ν: Validator x: Value ρ: Redeemer core core
44. PLUTUS Input Output ν: Validator x: Value ρ: Redeemer ν(ρ) ≟ True core core
45. PLUTUS Input Output ν: Validator x: Value ρ: Redeemer ν(ρ) ≟ True ν: Validator x: Value ρ: Redeemer core core core core
46. PLUTUS Input Output ν: Validator x: Value ρ: Redeemer ν(ρ) ≟ True ν: Validator x: Value ρ: Redeemer δ: Data core core core core core
47. PLUTUS Input Output ν: Validator x: Value ρ: Redeemer ν(ρ) ≟ True ν: Validator x: Value ρ: Redeemer δ: Data σ: State core core core core core
48. PLUTUS Input Output ν: Validator x: Value ρ: Redeemer ν(ρ) ≟ True ν: Validator x: Value ρ: Redeemer ν(ρ, δ, σ, x) ≟ True δ: Data σ: State core core core core core
49. PLUTUS ν: Validator x: Value ρ: Redeemer ν(ρ, δ, σ, x) ≟ True δ: Data σ: State Extended UTxO core core core
50. PLUTUS ν: Validator x: Value ρ: Redeemer ν(ρ, δ, σ, x) ≟ True δ: Data σ: State Extended UTxO Preserves the superior structure of UTxO ledgers core core core
51. PLUTUS ν: Validator x: Value ρ: Redeemer ν(ρ, δ, σ, x) ≟ True δ: Data σ: State Extended UTxO Preserves the superior structure of UTxO ledgers Greatly increases the expressive power of scripts core core core
52. PLUTUS Extended UTxO Preserves the superior structure of UTxO ledgers Greatly increases the expressive power of scripts
53. PLUTUS Extended UTxO Preserves the superior structure of UTxO ledgers Greatly increases the expressive power of scripts data flows with value
54. PLUTUS Extended UTxO Preserves the superior structure of UTxO ledgers Greatly increases the expressive power of scripts data flows with value scripts have an identity
55. PLUTUS Extended UTxO Preserves the superior structure of UTxO ledgers Greatly increases the expressive power of scripts data flows with value scripts have an identity invariants across transaction chains
56. PLUTUS Safety & Security Superior Ledger Full Stack
57. PLUTUS
58. PLUTUS What does it take to write a smart contract application?
59. PLUTUS Simple crowdfunding
60. PLUTUS Simple crowdfunding 1. Payment into campaign until a payment deadline
61. PLUTUS Simple crowdfunding 1. Payment into campaign until a payment deadline 2. If funding goal reached, campaign owner can collect funds
62. PLUTUS Simple crowdfunding 1. Payment into campaign until a payment deadline 2. If funding goal reached, campaign owner can collect funds 3. If funding goal not reached, refunds can be obtained by contributors
63. PLUTUS Simple crowdfunding 1. Payment into campaign until a payment deadline 2. If funding goal reached, campaign owner can collect funds 3. If funding goal not reached, refunds can be obtained by contributors 4. If campaign owner does not collect by collection deadline, contributors can also obtain refunds
64. PLUTUS 1. Payment into campaign until a payment deadline 2. If funding goal reached, campaign owner can collect funds 3. If funding goal not reached, refunds can be obtained by contributors 4. If campaign owner does not collect by collection deadline, contributors can also obtain refunds
65. PLUTUS 1. Payment into campaign until a payment deadline 2. If funding goal reached, campaign owner can collect funds 3. If funding goal not reached, refunds can be obtained by contributors 4. If campaign owner does not collect by collection deadline, contributors can also obtain refunds pragma solidity ^0.4.6; contract WinnerTakesAll { uint minimumEntryFee; uint public deadlineProjects; uint public deadlineCampaign; uint public winningFunds; address public winningAddress; struct Project { address addr; string name; string url; uint funds; bool initialized; } … Solidity (on-chain)
66. PLUTUS pragma solidity ^0.4.6; contract WinnerTakesAll { uint minimumEntryFee; uint public deadlineProjects; uint public deadlineCampaign; uint public winningFunds; address public winningAddress; struct Project { address addr; string name; string url; uint funds; bool initialized; } … Solidity (on-chain) var Web3 = require('web3'); var web3 = new Web3(); web3.setProvider(new web3.providers.HttpProvider(”http:… var accounts = web3.eth.accounts; accounts.forEach(function(v) { $(”#supportFrom”).append(”<opt… $(”#projectAddr”).append(”<opt… }); var compiled = web3.eth.compile.so… var code = compiled.code; var abi = compiled.info.abiDefinit… var contract = web3.eth.contract(a… … JavaScript (off-chain) +
67. PLUTUS pragma solidity ^0.4.6; contract WinnerTakesAll { uint minimumEntryFee; uint public deadlineProjects; uint public deadlineCampaign; uint public winningFunds; address public winningAddress; struct Project { address addr; string name; string url; uint funds; bool initialized; } … Solidity var Web3 = require('web3'); var web3 = new Web3(); web3.setProvider(new web3.providers.HttpProvider(”http:… var accounts = web3.eth.accounts; accounts.forEach(function(v) { $(”#supportFrom”).append(”<opt… $(”#projectAddr”).append(”<opt… }); var compiled = web3.eth.compile.so… var code = compiled.code; var abi = compiled.info.abiDefinit… var contract = web3.eth.contract(a… … JavaScript
68. PLUTUS pragma solidity ^0.4.6; contract WinnerTakesAll { uint minimumEntryFee; uint public deadlineProjects; uint public deadlineCampaign; uint public winningFunds; address public winningAddress; struct Project { address addr; string name; string url; uint funds; bool initialized; } … Solidity var Web3 = require('web3'); var web3 = new Web3(); web3.setProvider(new web3.providers.HttpProvider(”http:… var accounts = web3.eth.accounts; accounts.forEach(function(v) { $(”#supportFrom”).append(”<opt… $(”#projectAddr”).append(”<opt… }); var compiled = web3.eth.compile.so… var code = compiled.code; var abi = compiled.info.abiDefinit… var contract = web3.eth.contract(a… … JavaScript off-chain (wallet) on-chain (transaction)
69. PLUTUS pragma solidity ^0.4.6; contract WinnerTakesAll { uint minimumEntryFee; uint public deadlineProjects; uint public deadlineCampaign; uint public winningFunds; address public winningAddress; struct Project { address addr; string name; string url; uint funds; bool initialized; } … Solidity var Web3 = require('web3'); var web3 = new Web3(); web3.setProvider(new web3.providers.HttpProvider(”http:… var accounts = web3.eth.accounts; accounts.forEach(function(v) { $(”#supportFrom”).append(”<opt… $(”#projectAddr”).append(”<opt… }); var compiled = web3.eth.compile.so… var code = compiled.code; var abi = compiled.info.abiDefinit… var contract = web3.eth.contract(a… … JavaScript off-chain (wallet) on-chain (transaction) two-level (staged) programming model JavaScript Solidity
70. PLUTUS Solidity JavaScript off-chain (wallet) on-chain (transaction) two-level (staged) programming model ad hoc
71. PLUTUS Solidity JavaScript off-chain (wallet) on-chain (transaction) two-level (staged) programming model ad hoc inconvenient
72. PLUTUS Solidity JavaScript off-chain (wallet) on-chain (transaction) two-level (staged) programming model ad hoc inconvenient complex
73. PLUTUS Solidity JavaScript off-chain (wallet) on-chain (transaction) two-level (staged) programming model ad hoc inconvenient complex fragile
74. PLUTUS off-chain (wallet) on-chain (transaction) two-level (staged) programming model
75. PLUTUS Haskell off-chain (wallet) on-chain (transaction) two-level (staged) programming model
76. PLUTUS Haskell (Plutus Tx) Haskell off-chain (wallet) on-chain (transaction) two-level (staged) programming model
77. PLUTUS Haskell (Plutus Tx) Haskell off-chain (wallet) on-chain (transaction) two-level (staged) programming model meta programming
78. PLUTUS Haskell (Plutus Tx) Haskell off-chain (wallet) on-chain (transaction) two-level (staged) programming model meta programming integrated
79. PLUTUS Haskell (Plutus Tx) Haskell off-chain (wallet) on-chain (transaction) two-level (staged) programming model meta programming integrated compact
80. PLUTUS Haskell (Plutus Tx) Haskell off-chain (wallet) on-chain (transaction) two-level (staged) programming model meta programming integrated compact robust
81. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do Haskell
82. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" Haskell
83. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey Haskell
84. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript Haskell
85. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript (Ledger.scriptAddress (contributionScript campaign)) Haskell
86. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript (Ledger.scriptAddress (contributionScript campaign)) value Haskell
87. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript (Ledger.scriptAddress (contributionScript campaign)) value DataScript (Ledger.lifted ownPK) Haskell
88. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript (Ledger.scriptAddress (contributionScript campaign)) value DataScript (Ledger.lifted ownPK) register (refundTrigger campaign) (refundHandler (Ledger.hashTx tx) campaign) contributionScript :: Campaign -> ValidatorScript Haskell
89. PLUTUS Haskell contributionScript :: Campaign -> ValidatorScript
90. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = Haskell
91. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Haskell
92. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> Plutus Tx Haskell
93. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx Plutus Tx Haskell
94. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Plutus Tx Haskell
95. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && Plutus Tx Haskell
96. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && Plutus Tx Haskell
97. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Plutus Tx Haskell
98. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && Plutus Tx Haskell
99. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && h <= collectionDeadline && Plutus Tx Haskell
100. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && h <= collectionDeadline && totalInputs >= target && Plutus Tx Haskell
101. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && h <= collectionDeadline && totalInputs >= target && $$(txSignedBy) p campaignOwner Plutus Tx Haskell
102. PLUTUS contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && h <= collectionDeadline && totalInputs >= target && $$(txSignedBy) p campaignOwner in $$(P.errorIfNot) isValid ||]) Plutus Tx Haskell
103. PLUTUS Safety & Security Superior Ledger Full Stack
104. PLUTUS Safety & Security Superior Ledger Full Stack
105. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript (Ledger.scriptAddress (contributionScript campaign)) value DataScript (Ledger.lifted ownPK) register (refundTrigger campaign) (refundHandler (Ledger.hashTx tx) campaign) contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && h <= collectionDeadline && totalInputs >= target && $$(txSignedBy) p campaignOwner in $$(P.errorIfNot) isValid ||]) off-chain on-chain
106. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript (Ledger.scriptAddress (contributionScript campaign)) value DataScript (Ledger.lifted ownPK) register (refundTrigger campaign) (refundHandler (Ledger.hashTx tx) campaign) contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && h <= collectionDeadline && totalInputs >= target && $$(txSignedBy) p campaignOwner in $$(P.errorIfNot) isValid ||]) core off-chain on-chain
107. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript (Ledger.scriptAddress (contributionScript campaign)) value DataScript (Ledger.lifted ownPK) register (refundTrigger campaign) (refundHandler (Ledger.hashTx tx) campaign) contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && h <= collectionDeadline && totalInputs >= target && $$(txSignedBy) p campaignOwner in $$(P.errorIfNot) isValid ||]) core core off-chain on-chain
108. PLUTUS contribute :: Campaign -> Value -> MockWallet () contribute campaign value = do when (value <= 0) $ throwOtherError "Must contribute a positive value" ownPK <- ownPubKey tx <- payToScript (Ledger.scriptAddress (contributionScript campaign)) value DataScript (Ledger.lifted ownPK) register (refundTrigger campaign) (refundHandler (Ledger.hashTx tx) campaign) contributionScript :: Campaign -> ValidatorScript contributionScript campaign = ValidatorScript (validator `apply` campaign) where validator = Ledger.fromCompiledCode $$(PlutusTx.compile [|| (\Campaign{..} action contrib tx -> let PendingTx ps outs _ _ (Height h) _ _ = tx isValid = case action of Refund -> h > collectionDeadline && contributorOnly outs && $$(txSignedBy) tx contrib Collect -> h > deadline && h <= collectionDeadline && totalInputs >= target && $$(txSignedBy) p campaignOwner in $$(P.errorIfNot) isValid ||]) core core off-chain on-chain
109. PLUTUS This is Plutus! Safety & Security Superior Ledger Full Stack