Fair Computation using Enclaves and Shared Ledger Rohit Sinha , Siva - PowerPoint PPT Presentation

Fair Computation using Enclaves and Shared Ledger Rohit Sinha , Siva Gaddam, and Ranjit Kumaresan Open Source Enclaves Workshop 2019

Transparent Mint

Transparent Mint Alice Mint

Transparent Mint Merchant ID Date Amount Alice 2014-06-03 
 52544965 $23.00 13:37 PM User’s TX Data … … … 2014-06-29 
 12144989 $48.12 20:49 PM Merchant ID Category 52544965 Restaurants Mint’s 
 Proprietary … … Data 12144989 Gas Stations Mint

Transparent Mint Merchant ID Date Amount Alice 2014-06-03 
 52544965 $23.00 13:37 PM User’s TX Data … … … 2014-06-29 
 12144989 $48.12 20:49 PM Compute 
 Provider Report Merchant ID Category 52544965 Restaurants Mint’s 
 Proprietary … … Data 12144989 Gas Stations Mint

Transparent Mint Merchant ID Date Amount Alice 2014-06-03 
 52544965 $23.00 13:37 PM User’s TX Data … … … 2014-06-29 
 12144989 $48.12 20:49 PM Compute 
 Provider Report Merchant ID Category 52544965 Restaurants Mint’s 
 Proprietary … … Data 12144989 Gas Stations Mint

Transparent Mint Merchant ID Date Amount Alice Bank A 2014-06-03 
 52544965 $23.00 13:37 PM User’s TX Data … … … 2014-06-29 
 12144989 $48.12 20:49 PM Compute 
 Provider Report Merchant ID Category 52544965 Restaurants Mint’s 
 Proprietary … … Data 12144989 Gas Stations Mint Bank B

Towards Transparency via Privacy and Fairness Alice Bank A Compute 
 Provider Report Mint Bank B


 Towards Transparency via Privacy and Fairness Alice Bank A Privacy : Only reveal f(Alice_txs, Mint_db) 
 Compute 
 Provider Report Mint Bank B


 Towards Transparency via Privacy and Fairness Alice Bank A Privacy : Only reveal f(Alice_txs, Mint_db) 
 Compute 
 Fairness : if anyone gets Provider the output, then so must Report all honest parties 
 Mint Bank B


 Towards Transparency via Privacy and Fairness Alice Bank A Privacy : Only reveal f(Alice_txs, Mint_db) 
 Compute 
 Fairness : if anyone gets Provider the output, then so must Report all honest parties 
 Impossible in Malicious Setting [Cleve86] Mint Bank B

Fair Computation ➔ Fair Reconstruction

Fair Computation ➔ Fair Reconstruction (Unfair) Secure Computation { } k 1 { } TEE { } k o k 2

Fair Computation ➔ Fair Reconstruction (Unfair) Secure Computation { } k 1 { } TEE { } k o k 2 Systems based on Intel SGX 
 VC3 for Map-Reduce [SCF+15] Opaque for Spark [ZDB+17] ObliDB [EZ17] , StealthDB [GVG17] for SQL

Fair Computation ➔ Fair Reconstruction (Unfair) Secure Computation { } k 1 { } TEE { } k o k 2 Systems based on Intel SGX 
 VC3 for Map-Reduce [SCF+15] Opaque for Spark [ZDB+17] ObliDB [EZ17] , StealthDB [GVG17] for SQL

Fair Computation ➔ Fair Reconstruction Fair Reconstruction (Unfair) Secure Computation { } Ledger … k 1 { } TEE { } k o TEE TEE k 2 Systems based on Intel SGX 
 k o k o k o VC3 for Map-Reduce [SCF+15] Opaque for Spark [ZDB+17] ObliDB [EZ17] , StealthDB [GVG17] for SQL

Fair Computation ➔ Fair Reconstruction Fair Reconstruction (Unfair) Secure Computation { } Ledger … k 1 { } TEE { } k o TEE TEE k 2 Systems based on Intel SGX 
 k o k o k o VC3 for Map-Reduce [SCF+15] Fair n-party broadcast using 
 Opaque for Spark [ZDB+17] t < n TEE nodes and a shared ledger 
 (corruption threshold t) ObliDB [EZ17] , StealthDB [GVG17] for SQL

Fair Computation ➔ Fair Reconstruction Fair Reconstruction (Unfair) Secure Computation { } Ledger … k 1 { } TEE { } k o TEE TEE k 2 Systems based on Intel SGX 
 k o k o k o VC3 for Map-Reduce [SCF+15] Fair n-party broadcast using 
 Opaque for Spark [ZDB+17] t < n TEE nodes and a shared ledger 
 (corruption threshold t) ObliDB [EZ17] , StealthDB [GVG17] for SQL [CGJ+17]: all n parties need TEE

Fair Collaborative Computation

Fair Collaborative Computation TEE Collective Revenue Capture ML 
 Fair broadcast of model train

Fair Collaborative Computation TEE Collective Revenue Capture ML 
 Fair broadcast of model train ML 
 ML 
 TEE train infer prediction data Crowdsourced Machine Learning 
 Fair exchange of data and prediction

2-Party Fair Computation: Strawman

2-Party Fair Computation: Strawman TEE

2-Party Fair Computation: Strawman { } { } out out TEE

2-Party Fair Computation: Strawman { } { } out out Enc(pk_Alice, k y ) TEE

2-Party Fair Computation: Strawman { } { } out out Enc(pk_Alice, k y ) TEE

2-Party Fair Computation: Strawman { } { } out out Enc(pk_Alice, k y ) TEE

2-Party Fair Computation: Strawman { } { } out out Enc(pk_Alice, k y ) TEE

Bulletin Board Abstraction [CGJ+17]

Bulletin Board Abstraction [CGJ+17] Ledger …

Bulletin Board Abstraction [CGJ+17] Ledger … • post(x) returns (idx, σ )

Bulletin Board Abstraction [CGJ+17] Ledger … σ x • post(x) returns (idx, σ )

Bulletin Board Abstraction [CGJ+17] Ledger … σ x • post(x) returns (idx, σ ) • getContent(idx) returns (x, σ )

Bulletin Board Abstraction [CGJ+17] Ledger … σ x • post(x) returns (idx, σ ) • getContent(idx) returns (x, σ ) • getHeight() returns (idx)

2-Party Fair Computation Ledger … TEE

2-Party Fair Computation Ledger … TEE { } { } out out

2-Party Fair Computation Ledger … TEE { } { } out out

2-Party Fair Computation Ledger … Enc(pk_Alice, k y ) || TEE { } { } out out

2-Party Fair Computation Ledger … Enc(pk_Alice, k y ) || TEE { } { } out out

2-Party Fair Computation Ledger … Enc(pk_Alice, k y ) || σ TEE { } { } out out

2-Party Fair Computation Ledger … Enc(pk_Alice, k y ) || σ TEE { } { } out out

n-Party Fair Broadcast: Strawman Ledger … TEE

n-Party Fair Broadcast: Strawman Ledger … TEE

n-Party Fair Broadcast: Strawman Ledger … TEE

n-Party Fair Broadcast: Strawman Ledger … Enc(pk_Alice, k y ) || Enc(pk_BankA, k y ) || Enc(pk_BankA, k y ) TEE

n-Party Fair Broadcast: Strawman Ledger … Enc(pk_Alice, k y ) || Enc(pk_BankA, k y ) || Enc(pk_BankA, k y ) TEE

n-Party Fair Broadcast: Strawman Ledger … Enc(pk_Alice, k y ) || Enc(pk_BankA, k y ) || Enc(pk_BankA, k y ) TEE

n-Party Fair Broadcast: Strawman Ledger … Enc(pk_Alice, k y ) || Enc(pk_BankA, k y ) || Enc(pk_BankA, k y ) TEE Enc(pk_BankA, k y )

n-Party Fair Broadcast

n-Party Fair Broadcast { } out

n-Party Fair Broadcast { } out

n-Party Fair Broadcast { } out Ledger …

n-Party Fair Broadcast { } out Ledger …

n-Party Fair Broadcast { } out Ledger …

n-Party Fair Broadcast { } out Ledger …

n-Party Fair Broadcast { } out Ledger …

n-Party Fair Broadcast { } out Ledger …

n-Party Fair Broadcast { } out Ledger …

n-Party Fair Broadcast { } out Ledger …

n-Party Fair Broadcast { } out Ledger … = E pk_Alice (k y )

n-Party Fair Broadcast { } out Ledger … = E pk_Alice (k y )

n-Party Fair Broadcast { } out Ledger … = E pk_Alice (k y )

n-Party Fair Broadcast { } out Ledger … = E pk_Alice (k y )

n-Party Fair Broadcast { } out Ledger … = E pk_Alice (k y )

Q/A https://eprint.iacr.org/2019/178