SPDZ-2: A C++ repository from ishaq

Software for the SPDZ and MASCOT secure multi-party computation protocols. See Programs/Source/ for some example MPC programs, and tutorial.md for a basic tutorial.

Requirements:

GCC
MPIR library, compiled with C++ support (use flag --enable-cxx when running configure)
libsodium library, tested against 1.0.11
CPU supporting AES-NI and PCLMUL
Python 2.x, ideally with gmpy package (for testing)

OS X:

g++ might actually refer to clang, in which case you need to change CONFIG to use GCC instead.
It has been reported that MPIR has to be compiled with GCC for the linking to work: ./configure CC=<path to GCC gcc> CXX=<path to GCC g++> --enable-cxx

To compile SPDZ:

Optionally, edit CONFIG and CONFIG.mine so that the following variables point to the right locations:

PREP_DIR: this should be a local, unversioned directory to store preprocessing data (defaults to Player-Data in the working directory)

Run make (use the flag -j for faster compilation with multiple threads)

To setup for the online phase

Run:

Scripts/setup-online.sh

This sets up parameters for the online phase for 2 parties with a 128-bit prime field and 40-bit binary field, and creates fake offline data (multiplication triples etc.) for these parameters.

Parameters can be customised by running

Scripts/setup-online.sh <nparties> <nbitsp> <nbits2>

To compile a program

To compile the program in ./Programs/Source/tutorial.mpc, run:

./compile.py tutorial

This creates the bytecode and schedule files in Programs/Bytecode/ and Programs/Schedules/

To run a program

To run the above program (on one machine), first run:

./Server.x 2 5000 &

(or replace 5000 with your desired port number)

Then run both parties' online phase:

./Player-Online.x -pn 5000 0 tutorial

./Player-Online.x -pn 5000 1 tutorial (in a separate terminal)

Or, you can use a script to do the above automatically:

Scripts/run-online.sh tutorial

To run a program on two different machines, firstly the preprocessing data must be copied across to the second machine (or shared using sshfs), and secondly, Player-Online.x needs to be passed the machine where Server.x is running. e.g. if this machine is name diffie on the local network:

./Player-Online.x -pn 5000 -h diffie 0 tutorial

./Player-Online.x -pn 5000 -h diffie 1 tutorial

Compiling and running programs from external directories

Programs can also be edited, compiled and run from any directory with the above basic structure. So for a source file in ./Programs/Source/, all SPDZ scripts must be run from ./. The setup-online.sh script must also be run from ./ to create the relevant data. For example:

spdz$ cd ../
$ mkdir myprogs
$ cd myprogs
$ mkdir -p Programs/Source
$ vi Programs/Source/test.mpc
$ ../spdz/compile.py test.mpc
$ ls Programs/
Bytecode  Public-Input  Schedules  Source
$ ../spdz/Scripts/setup-online.sh
$ ls
Player-Data Programs
$ ../spdz/Scripts/run-online.sh test

Offline phase (MASCOT)

In order to compile the MASCOT code, the following must be set in CONFIG or CONFIG.mine:

USE_GF2N_LONG = 1

It also requires SimpleOT:

git submodule update --init SimpleOT
cd SimpleOT
make

If SPDZ has been built before, any compiled code needs to be removed:

make clean

HOSTS must contain the hostnames or IPs of the players, see HOSTS.example for an example.

Then, MASCOT can be run as follows:

host1:$ ./ot-offline.x -p 0 -c

host2:$ ./ot-offline.x -p 1 -c

ishaq/SPDZ-2