swanky: A suite of rust libraries for secure multi-party computation

swanky provides a suite of rust libraries for doing secure multi-party computation (MPC).

This fork extends fancy-garbling by adding support for arithmetic operations in GF(2^k). See below for concrete changes.

• fancy-garbling: Boolean and arithmetic garbled circuits.
  • twopac: Two-party garbled-circuit-based secure computation.
• ocelot: Oblivious transfer and oblivious PRFs.
• popsicle: Private-set intersection.
• scuttlebutt: Core MPC-related primitives used by various swanky libraries.

A Note on Security

swanky is currently considered prototype software. Do not deploy it in production, or trust it with sensitive data.

License

swanky from Galois: MIT License

extension: MIT License

Authors

• Brent Carmer bcarmer@galois.com
• Alex J. Malozemoff amaloz@galois.com
• Marc Rosen marc@galois.com

Extension

• Erik Pohle erik.pohle@esat.kuleuven.be
• Robbe Vermeiren
• Elias Wils

Extension

Arithmetic garbled circuits now support addition, constant-multiplication and projection in the field GF(2^k) for k ≤ 8.

Most of the changes in the library are the introduction of a proper Modulus type (instead of the old u16)

pub enum Modulus {
    /// Integer modulus for Zq.
    Zq { q: u16 },
    /// Irreducible polynomial for GF(2^4).
    GF4 { p: u8 },
    /// Irreducible polynomial for GF(2^8).
    GF8 { p: u16 },
    /// Irreducible polynomial for GF(2^k).
    GFk { k: u8, p: u16 }
}

which specifies the ring/field and the modulus (respectively the Irreducible polynomial). All existing tests, bundles and the CRT code have been adapted to work and output Modulus::Zq moduli.

Consequently, the Wire type was extended as well to allow dedicated representation of a wire label in GF(2^k)^l.

pub enum Wire {
    ...
    /// An element in the field GF(2^k) is represented by the coefficients of the polynomial
    /// EXAMPLE: x^3 + x + 1 in GF(2^4)
    ///   ===>   Elt: u16 = (0000...0 1 0 1 1) = 11
    ///
    ///
    /// Representation of a wire in GF(2^4)
    GF4 {
        /// Irreducible polynomial.
        p: u8,
        /// A list of GF(2^4) elements.
        elts: Vec<u16>,
    },
    /// Representation of a wire in GF(2^8)
    GF8 {
        /// Irreducible polynomial
        p: u16,
        /// A list of GF(2^4) elements
        elts: Vec<u16>,
    },
    /// Representation of a wire in GF(2^k)
    GFk {
        /// k
        k: u8,
        /// Irreducible polynomial.
        p: u16,
        /// A list of GF(2^4) elements.
        elts: Vec<u16>,
    },
}

Thus, wires and gates can perform either arithmetic in Z_q or GF(2^k), and, as usual, projection gates translate between moduli.

Acknowledgments

This material is based upon work supported by the ARO and DARPA under Contract No. W911NF-15-C-0227 and by DARPA and SSC Pacific under Contract No. N66001-15-C-4070.

Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the ARO, SSC Pacific, and DARPA.

Copyright © 2019 Galois, Inc.