Privacy Precompile: enables private transactions with extended obfuscated fields #1234

SatpalSandhu61 · 2021-08-11T10:34:34Z

Introduction

Add support for privacy precompiled contract to orchestrate the execution of private transactions. This new approach allows extending the obfuscated fields of a private transaction.

So far data field was the only obfuscated field of a private transaction, other fields were visible from non-participants node. This new precompiled contract approach allows to obfuscate data, to, and gasLimit. In some future enhancement, we could use this same approach to obfuscate the sender address.

This introduces the concept of Privacy Marker Transactions (PMT), which is a standard public transaction sent to the privacy precompiled contract to get private transactions executed

to field is always be set to privacy precompiled at address 0x000000000000000000000000000000000000007a
data field is set to the Tessera key of the extended private transaction

When processing a PMT the privacy precompile of participant nodes executes the extended private transaction corresponding to the Tessera key in PMT data. The final execution of the private transaction is identical to the usual private transaction in particular it is the private state of participants that is mutated.

New JSON-RPC methods

eth_distributePrivateTransaction enables to push a private transaction payload to Tessera
eth_getPrivacyPrecompileAddress that returns the precompile address (so far this is fixed to 0x000000000000000000000000000000000000007a)

Configuration

Add genesis field "privacyPrecompileBlock": 0, under config section which defines block number, after which privacy precompiled contract is enabled
Pass CLI --privacymarker.enable flag when starting node

Transaction flow details

Private Transaction Submission

Node signing

User sends the transaction to GoQuorum using eth_sendTransaction as normal in particular passing privateFor and to field set to the private contract address (or nil for contract deployment)
GoQuorum prepare and signs the private transaction containing all fields
GoQuorum sends signed private transaction to Tessera, which distributes the private transaction to other participants and returns the private hash
GoQuorum creates the ‘Privacy Marker Transaction’ (PMT), where:
- data is the private hash of the transaction stored in Tessera.
- to is the privacy precompile address 0x000000000000000000000000000000000000007a
- PMT is signed using the same account as the one used for the private transaction
GoQuorum submits the PMT to the tx pool as any standard public transaction

External signing

User creates and externally sign private tx as normal (with signature v modified value) particular setting privateFor and to field set to the private contract address (or nil for contract deployment)
User calls eth_distributePrivateTransaction with the externally signed private transaction. On this call, GoQuorum pushes the private transaction payload to Tessera that encrypts it and returns private tx manager hash
User creates and externally signs the PMT
- data should be the private tx manager hash got on previous call to eth_distributePrivateTransaction
- to should be the privacy precompile address 0x000000000000000000000000000000000000007a
User sends the signed PMT with eth_sendRawTransaction

Transaction Processing

When executing the PMT

Transaction is dispatch to the privacy precompiled contract for execution
Privacy precompile reads private transaction hash from PMT data field as private hash
Privacy precompile queries Tessera with private hash, if no data is found, then this node is not a participant so no further processing is needed
Privacy precompile triggers the EVM execution of the private transaction using the private state as per normal private transaction

… extended obfuscated fields"" This reverts commit cd945b0

…xn gas value (#4) Use intrinsicGas on privacy marker transaction, rather than private txn gas value

baptiste-b-pegasys

it may have an issue with mps ATs, checking that locally.

[ {
  "file" : "src/specs/01_basic/extend_private_contract.spec",
  "line" : 1,
  "col" : 1,
  "message" : "Scenario: Extend contract to a new party, creator cancels extension 1%0AStep: <fromNode> cancels <contractName>%0AConcept Execution Failure: 'org.opentest4j.AssertionFailedError: %0AExpecting:%0A <org.web3j.protocol.core.Response$Error@237a1875>%0Ato be equal to:%0A <null>%0Abut was not.'"
} ]

baptiste-b-pegasys · 2021-08-11T13:26:15Z

accounts/abi/bind/bind_quorum_test.go

+	return tx, nil
+}
+
+type mockTransactor struct {


can we generate that mock with an interface?

baptiste-b-pegasys · 2021-08-11T13:46:08Z

core/types/transaction.go

@@ -581,6 +581,10 @@ func (tx *Transaction) SetPrivate() {
 	}
 }

+func (tx *Transaction) IsPrivacyMarker() bool {


Suggested change

func (tx *Transaction) IsPrivacyMarker() bool {

func (tx *Transaction) HasPrivacyMarker() bool {

many "is privacy marker" changes, I prefer with has, or use

This hasn't changed since the PR was originally reviewed. We don't want to make further changes at this late stage now.

baptiste-b-pegasys · 2021-08-11T13:48:32Z

accounts/abi/bind/bind_quorum_test.go

+	return tx, nil
+}
+
+type mockTransactor struct {


can it be generated.

This hasn't changed since the PR was originally reviewed. We don't want to make changes at this late stage.

baptiste-b-pegasys · 2021-08-11T13:49:27Z

signer/core/api.go

@@ -533,7 +533,7 @@ func (api *SignerAPI) SignTransaction(ctx context.Context, args SendTxArgs, meth
 		result SignTxResponse
 		msgs   *ValidationMessages
 	)
-	if args.IsPrivate {
+	if args.IsPrivate || args.isPrivacyMarker() {


Suggested change

if args.IsPrivate || args.isPrivacyMarker() {

if args.IsPrivate || args.hasPrivacyMarker() {

This hasn't changed since the PR was originally reviewed, so we'd prefer not to make changes now.

extension/api.go

internal/ethapi/api.go

accounts/abi/bind/base.go

chris-j-h · 2021-08-11T14:35:04Z

it may have an issue with mps ATs, checking that locally.

[ {
  "file" : "src/specs/01_basic/extend_private_contract.spec",
  "line" : 1,
  "col" : 1,
  "message" : "Scenario: Extend contract to a new party, creator cancels extension 1%0AStep: <fromNode> cancels <contractName>%0AConcept Execution Failure: 'org.opentest4j.AssertionFailedError: %0AExpecting:%0A <org.web3j.protocol.core.Response$Error@237a1875>%0Ato be equal to:%0A <null>%0Abut was not.'"
} ]

@baptiste-b-pegasys this PR requires a change to the atests - I am in the process of preparing that PR

…r transaction in ABI (#6)

accounts/abi/bind/base.go

core/state_processor.go

ricardolyn

LGTM

chris-j-h and others added 2 commits August 9, 2021 11:11

Revert "Revert "Privacy Precompile: enables private transactions with…

b6ab8ac

… extended obfuscated fields"" This reverts commit cd945b0

Use intrinsicGas on privacy marker transaction, rather than private t…

68ae219

…xn gas value (#4) Use intrinsicGas on privacy marker transaction, rather than private txn gas value

SatpalSandhu61 requested review from nmvalera, ricardolyn, baptiste-b-pegasys, chris-j-h, Krish1979 and nicolae-leonte-go August 11, 2021 10:34

baptiste-b-pegasys reviewed Aug 11, 2021

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SatpalSandhu61 and others added 2 commits August 11, 2021 16:37

Remove unwanted comment

2fac64d

Use Intrinsic Gas value when creating externally signed privacy marke…

2fe2ad1

…r transaction in ABI (#6)

ricardolyn reviewed Aug 12, 2021

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Fix gasPool issues for precompile and MPS. (#7)

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Krish1979 approved these changes Aug 13, 2021

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SatpalSandhu61 mentioned this pull request Aug 13, 2021

Docs for privacy marker transactions Consensys/doc.goquorum#122

Merged

Krish1979 merged commit 0e29241 into Consensys:master Aug 13, 2021

SatpalSandhu61 deleted the consensysengineering-privacy-support-using-precompile-v4 branch August 17, 2021 14:39

SatpalSandhu61 mentioned this pull request Aug 18, 2021

New API methods which were added for supporting privacy marker transactions Consensys/web3js-quorum#24

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Privacy Precompile: enables private transactions with extended obfuscated fields #1234

Privacy Precompile: enables private transactions with extended obfuscated fields #1234

SatpalSandhu61 commented Aug 11, 2021

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baptiste-b-pegasys Aug 11, 2021

SatpalSandhu61 Aug 11, 2021

baptiste-b-pegasys Aug 11, 2021

SatpalSandhu61 Aug 11, 2021

baptiste-b-pegasys Aug 11, 2021

SatpalSandhu61 Aug 11, 2021

chris-j-h commented Aug 11, 2021

ricardolyn left a comment

	func (tx *Transaction) IsPrivacyMarker() bool {
	func (tx *Transaction) HasPrivacyMarker() bool {

	if args.IsPrivate \|\| args.isPrivacyMarker() {
	if args.IsPrivate \|\| args.hasPrivacyMarker() {

Privacy Precompile: enables private transactions with extended obfuscated fields #1234

Privacy Precompile: enables private transactions with extended obfuscated fields #1234

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SatpalSandhu61 commented Aug 11, 2021

Introduction

New JSON-RPC methods

Configuration

Transaction flow details

Private Transaction Submission

Node signing

External signing

Transaction Processing

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