Ajith Suresh CrIS Lab, IISc * Indian Institute of Science (IISc), - PowerPoint PPT Presentation

Ajith Suresh CrIS Lab, IISc * Indian Institute of Science (IISc), Bangalore https://www.csa.iisc.ac.in/~cris ^ Aarhus University, Denmark

Outline q Privacy Preserving Machine Learning (PPML) q Secure Multi-party Computation (MPC) q Overview of Trident Protocol q Benchmarking Results AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Machine Learning (ML) Prediction – An Abstraction Model Query Parameters Result ML Algorithm Jasmine Aladdin (Model Owner) (Client) Privacy ?? AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Machine Learning (ML) Prediction – An Abstraction Query Model Parameters Result ML Algorithm Jasmine Aladdin (Model Owner) (Client) Privacy ?? AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Machine Learning (ML) Prediction – An Abstraction Model Query Parameters Result ML Algorithm Jasmine Aladdin (Model Owner) (Client) Privacy ?? AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Privacy Preserving Machine Learning (PPML) Model Query Parameters Result PPML Algorithm Jasmine Aladdin (Model Owner) (Client) MPC meets ML AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Secure Multi-party Computation (MPC) [Yao’82] ü A set of parties with private inputs wish to compute some joint function of their inputs. ü Goals of MPC: Correctness – Parties should correctly evaluate § the function output. Privacy – Nothing more than the function § output should be revealed AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Secure Multi-party Computation (MPC) [Yao’82] Trusted Third Party (TTP) AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trusted Third Party (TTP) AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

MPC MPC emulates TTP AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model v 4 parties v Honest majority v At most 1 corruption AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model v Data independent pre-processing v Fast online phase AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Sharing Semantics

Pre-processing

Pre-processing

+ = Online

Shares of

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model Ø Malicious security with guarantee of fairness AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model Ø Malicious security with guarantee of fairness Corrupt parties arbitrarily deviate AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model Ø Malicious security with guarantee of fairness Honest parties get output whenever corrupt parties get output AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Multiplication ( !. # ) Pre-processing Online Ref Security (#elements) (#elements) Araki et al’17 (3PC) 12 9 Abort AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Multiplication ( !. # ) Pre-processing Online Ref Security (#elements) (#elements) Araki et al’17 (3PC) 12 9 Abort ASTRA (3PC) 21 4 Fair AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Multiplication ( !. # ) Pre-processing Online Ref Security (#elements) (#elements) Araki et al’17 (3PC) 12 9 Abort ASTRA (3PC) 21 4 Fair Gordon et al.’18 (4PC) 2 4 Abort AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Multiplication ( !. # ) Pre-processing Online Ref Security (#elements) (#elements) Araki et al’17 (3PC) 12 9 Abort ASTRA (3PC) 21 4 Fair Gordon et al.’18 (4PC) 2 4 Abort Trident 3 3 Fair AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model Ø Malicious security with guarantee of fairness Ø Efficient Mixed World Conversions AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions Boolean World Boolean o Comparison, Bit Extraction … AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions Boolean World Boolean o Comparison, Bit Extraction … Arithmetic World o Addition, Multiplication … Arithmetic AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions Boolean World Boolean o Comparison, Bit Extraction … Arithmetic World o Addition, Multiplication … Garbled Arithmetic Garbled World o Division over rings … AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions Boolean Online Online Rounds Communication B2A B2G Up to 7 x 2 x - 67 x A2B G2B Range of improvement over ABY3 A2G Garbled Arithmetic G2A AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example min(% & + % ( , % * ) % , AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example ! " + x % AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example Arithmetic ! " + x % AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example Arithmetic A2B ! " + x % min(! " + ! % , ! + ) AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example Arithmetic Boolean A2B ! " + x % min(! " + ! % , ! + ) AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example Arithmetic Boolean A2B ! " + x % min(! " + ! % , ! + ) B2G AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example Arithmetic Boolean A2B ! " + x % min(! " + ! % , ! + ) B2G A2G ! - AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example Arithmetic Boolean A2B ! " + x % min(! " + ! % , ! + ) B2G A2G min ! " + ! % , ! + ÷ ! . ! . AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example Arithmetic Boolean A2B ! " + x % min(! " + ! % , ! + ) B2G A2G min ! " + ! % , ! + ÷ ! . ! . Garbled AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Mixed World Conversions – An Example Arithmetic Boolean A2B % & + x ( min(% & + % ( , % * ) B2G min(% & + % ( , % * ) A2G G2A min % & + % ( , % * ÷ % , % , % , Garbled AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model Ø Malicious security with guarantee of fairness Ø Efficient Mixed World Conversions Ø Special tools for PPML AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

) Dot Product !∎# = % * + . -+ &'( Pre-processing Online Ref Security (#elements) (#elements) ABY3 (3PC) 12d 9d Abort d – #elements in each vector AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

) Dot Product !∎# = % * + . -+ &'( Pre-processing Online Ref Security (#elements) (#elements) ABY3 (3PC) 12d 9d Abort ASTRA (3PC) 21d 2d+2 Fair d – #elements in each vector AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

) Dot Product !∎# = % * + . -+ &'( Pre-processing Online Ref Security (#elements) (#elements) ABY3 (3PC) 12d 9d Abort ASTRA (3PC) 21d 2d+2 Fair Trident 3 3 Fair d – #elements in each vector AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Non-linear Dot Activation Product Functions Bit Truncation Injection Tools for PPML Bit to Fixed Point Arithmetic Arithmetic Comparison AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020

Trident protocol Ø A new 4PC protocol over ring in the pre-processing model Ø Malicious security with guarantee of fairness Ø Efficient Mixed World Conversions Ø Special tools for PPML Ø Lower monetary cost in the outsourced setting AJITH SURESH | CRYPTOGRAPHY AND INFORMATION SECURITY LAB ,CSA, IISC 26-02-2020