Crypto Conditions. A Solid Foundation for ILP. Stefan Thomas

Transcription

1 Crypto Conditions A Solid Foundation for ILP Stefan Thomas

2 The Receipt 2

3 Connector gets receipt from ledger Umm... 3

4 Connector passes on the receipt Excuse me... 4

5 Connector passes on the receipt What's that thing? 5

6 Ledger Needs to Decide ROLLBACK? EXECUTE 6

7 Rollback on failure ROLLBACK EXECUTE 7

8 Execute on success ROLLBACK EXECUTE 8

9 What is success?

10 As a sender I want to be certain

11 As a sender I want to be certain that my donation was received

12 As a sender I want to be certain that the invoice was paid

13 As a sender I want to be certain that my debt is settled

14 As a sender I want

15 The Receipt Signed by recipient Proves receipt-of-funds Non-repudiable Might have data attached Pre-agreed before payment 15

16 How do we describe the receipt? ROLLBACK EXECUTE 16

17 How do we describe the receipt? ROLLBACK EXECUTE 17

18 How do we describe the receipt? ROLLBACK EXECUTE 18

19 Condition Describes some signed message Fulfilled by that message? 19

20 Why Are Conditions so Important? 20

21 Why Are Conditions so Important? EXECUTE 21

22 Why Are Conditions so Important? ROLLBACK EXECUTE 22

23 Conditions Must Be Bit-Perfect EXECUTE EXECUTE 23

24 Others Have Done The Hard Part 24

25 Are Simple Signatures Enough?

26 Single Signature Condition

27 Multi Signature Condition 2-of-3

28 Prior Art: Bitcoin Scripts 2 <K1> <K2> <K3> 3 CHECKMULTISIGVERIFY Forth-like language Many opcodes disabled Primary use case: m-of-n multi-signature 28

29 Other Ideas Pay-to-script-hash Andresen Tree Signatures Wuille Merkleized Abstract Syntax Trees (MAST) Rubin et al Script2 Blockstream Smart Signatures Allen et al State Channels Coleman 29

30 Security vs Flexibility Single Signature Turing Completeness

31 Security vs Flexibility Single Signature Turing Completeness Bit-perfect, standardized programming language

32 Security vs Flexibility Single Signature Turing Completeness "ActiveX of blockchain"

33 Security vs Flexibility Single Signature? Turing Completeness

34 Smart Oracles

35 Smart Oracle

36 Smart Oracle

37 Delegation

38 Single Signature If Bob says yes, then yes.

39 2-of-2 Multi Signature If Bob and Lina say yes, then yes.

40 2-of-3 Multi Signature If any two of Bob, Chandra, Lina say yes, then yes.

41 2-of-3 Multi Signature? If Bob and (Chandra or Lina) say yes, then yes.

42 Boolean Circuits Chandra Lina Bob

43 Boolean Circuits OR AND

44 Boolean Circuits OR m m-of-n AND

45 Boolean Circuits 1-of-n m m-of-n n-of-n

46 Boolean Circuits 1 m n 1-of-n m-of-n n-of-n

47 Putting it all together

48 Condition Types Signatures Thresholds

49 Condition Types Signatures Thresholds

50 Fulfillment

51 Signature Condition CONDITION = VARUINT BITMASK = 2 UINT256 HASH VARUINT MAX_FULLFILLMENT_LENGTH

52 Signature Condition CONDITION = VARUINT BITMASK = 2 UINT256 HASH VARUINT MAX_FULLFILLMENT_LENGTH HASH = SHA256( SHA256(" VARSTR MODULUS VARSTR MESSAGE_PREFIX )

53 Signature Condition cc:1:aml_0bgdrvk32fxtvmq6v1sskfrxaf7xhegei16vtaexsgi

54 Signature Fulfillment FULFILLMENT = VARUINT BITMASK = 2 VARSTR MODULUS VARSTR MESSAGE_PREFIX VARSTR MESSAGE UINT8[LENGTH(MODULUS)] SIGNATURE VARUINT BYTES_UNUSED

55 Signature Fulfillment cf: 1:AoABYTEyNWNiZGFmNWI3NDk0MzQ5YjE2NGUxMmRjZTRiN DBkMTI4MTNkYTY1ZDM4YTEyOTNmZDFhOWMwMTk2YzJlZjRm YWRhNjI2OWNjYzFhNzdjMTZhYjc2NmRhMGU0NzYxYzQ4Mjc 1Y2U4MzNmOGE5MzdkOWMyOWQzZDVlNmQyZTkMSGVsbG8gd2 9ybGQhFSBDb25kaXRpb25zIGFyZSBoZXJlIUFLExFQC5PXo Lli_CBpIEE0WOypkZL7wCf_eIWExJJEmdrt00ubso94DO7g IOLUTh5sRCuij29Yos1b_yE79gwA

56 Threshold Condition CONDITION = VARUINT BITMASK UINT256 HASH VARUINT MAX_FULLFILLMENT_LENGTH

57 Threshold Condition CONDITION = VARUINT BITMASK UINT256 HASH VARUINT MAX_FULLFILLMENT_LENGTH HASH = SHA256( SHA-256(" VARUINT THRESHOLD VARUINT NUM_ELEMENTS FOR EACH ELEMENT ELEMENT_CONDITION )

58 Threshold Condition cc:1:ar9qcvepdtnsct6sgwtx6cwflgbrp8tnqwijylaiey4vtai

59 Threshold Fulfillment FULFILLMENT = VARUINT BITMASK VARUINT THRESHOLD VARUINT NUM_ELEMENTS FOR EACH ELEMENT VARUINT PARAMS ELEMENT_CONDITION/FULFILLMENT

60 Threshold Fulfillment cf:1:aqicjywvnzkrboa8qdkcpc_c6sh-lnkpfu- COmv9j2e3ScuzAgKAAWExMjVjYmRhZjViNzQ5NDM0OWIxNjRl MTJkY2U0YjQwZDEyODEzZGE2NWQzOGExMjkzZmQxYTljMDE5N mmyzwy0zmfkytyynjljy2mxytc3yze2ywi3njzkytblndc2mw M0ODI3NWNlODMzZjhhOTM3ZDljMjlkM2Q1ZTZkMmU5DEhlbGx vihdvcmxkirugq29uzgl0aw9ucybhcmugagvyzsfbsxmruaut 16C5YvwgaSBBNFjsqZGS-8An_3iFhMSSRJna7dNLm7KPeAzu4 CDi1E4ebEQroo9vWKLNW_8hO_YMAA

61 Merkle Circuits

62 Threshold Fulfillment cf:1:aqicjywvnzkrboa8qdkcpc_c6sh-lnkpfu- COmv9j2e3ScuzAgKAAWExMjVjYmRhZjViNzQ5NDM0OWIxNjRl MTJkY2U0YjQwZDEyODEzZGE2NWQzOGExMjkzZmQxYTljMDE5N mmyzwy0zmfkytyynjljy2mxytc3yze2ywi3njzkytblndc2mw M0ODI3NWNlODMzZjhhOTM3ZDljMjlkM2Q1ZTZkMmU5DEhlbGx vihdvcmxkirugq29uzgl0aw9ucybhcmugagvyzsfbsxmruaut 16C5YvwgaSBBNFjsqZGS-8An_3iFhMSSRJna7dNLm7KPeAzu4 CDi1E4ebEQroo9vWKLNW_8hO_YMAA

63 Threshold Fulfillment cf:1:aqicjywvnzkrboa8qdkcpc_c6sh-lnkpfu- COmv9j2e3ScuzAgKAAWExMjVjYmRhZjViNzQ5NDM0OWIxNjRl MTJkY2U0YjQwZDEyODEzZGE2NWQzOGExMjkzZmQxYTljMDE5N mmyzwy0zmfkytyynjljy2mxytc3yze2ywi3njzkytblndc2mw M0ODI3NWNlODMzZjhhOTM3ZDljMjlkM2Q1ZTZkMmU5DEhlbGx vihdvcmxkirugq29uzgl0aw9ucybhcmugagvyzsfbsxmruaut 16C5YvwgaSBBNFjsqZGS-8An_3iFhMSSRJna7dNLm7KPeAzu4 CDi1E4ebEQroo9vWKLNW_8hO_YMAA

64 Threshold Fulfillment cf:1:aqicjywvnzkrboa8qdkcpc_c6sh-lnkpfu- COmv9j2e3ScuzAgKAAWExMjVjYmRhZjViNzQ5NDM0OWIxNjRl MTJkY2U0YjQwZDEyODEzZGE2NWQzOGExMjkzZmQxYTljMDE5N mmyzwy0zmfkytyynjljy2mxytc3yze2ywi3njzkytblndc2mw M0ODI3NWNlODMzZjhhOTM3ZDljMjlkM2Q1ZTZkMmU5DEhlbGx vihdvcmxkirugq29uzgl0aw9ucybhcmugagvyzsfbsxmruaut 16C5YvwgaSBBNFjsqZGS-8An_3iFhMSSRJna7dNLm7KPeAzu4 CDi1E4ebEQroo9vWKLNW_8hO_YMAA

65 Recap Two Condition Types Signature Threshold Conditions are constant size Falsy branches can be omitted Complex logic is delegated

66 Other Features Conditions can be generated from fulfillments Max fulfillment length in condition Extensible with new crypto primitives Required feature set in condition

67 First Editor's Draft Coming Soon Interledger.org