Obliv-C is a simple GCC wrapper that makes it easy to embed secure computation protocols inside regular C programs. The idea is simple: if you are performing a multi-party distributed computation with sensitive data, just write it in our Obliv-C langauge and compile/link it with your project. The result will be a secure cryptographic protocol that performs this operation without revealing any of the inputs or intermediate values of the computation to any of the parties. Only the outputs are finally shared.

Unfortunately, the instructions for Fedora and Mac OS might be a little out of date, since we discovered OPAM is now a dependency (#49). Please ping us if you figured out how to install Obliv-C on those systems.

1. Installation of dependencies.

• For Ubuntu: sudo apt-get install ocaml libgcrypt20-dev ocaml-findlib opam m4.
• For Fedora 27: sudo dnf install glibc-devel.i686 ocaml ocaml-ocamldoc ocaml-findlib ocaml-findlib-devel ocaml-ocamlbuild libgcrypt libgcrypt-devel perl-ExtUtils-MakeMaker perl-Data-Dumper.
• For Mac OS (with Macports): sudo port install gcc5 ocaml ocaml-findlib opam libgcrypt +devel.
• For Mac OS 10.15/11 (with homebrew): brew install gcc5 ocaml ocaml-findlib opam libgcrypt +devel. (+devel does not seem to be required on Mac OS 10.15).

2. If you are using OPAM as our package manager, and this is the first time you are using it, set it up:

   opam init
   opam switch 4.06.0
   eval `opam config env`
   opam install camlp4 ocamlfind ocamlbuild batteries
   

   Version 4.06.0 just happened to be the most recent version when we tested. You can check what you have by running opam switch list, and try a more recent one. Note that this step seems to be unnecessary under Fedora.

3. Git-clone this repository, and compile:

• For Linux: ./configure && make.
• For Mac OS (with Macports): CC=/opt/local/bin/gcc-mp-5 CPP=/opt/local/bin/cpp-mp-5 CFLAGS=/opt/local/include LIBRARY_PATH=/opt/local/lib ./configure && make.
• For Mac OS 10.15/11 (with homebrew): export CPATH=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ ; export LIBRARY_PATH=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib ; CC=/usr/local/bin/gcc-5 CPP=/usr/local/bin/cpp-5 ./configure && make. (Note: if only the Xcode command line tools are installed, set CPATH to /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/ instead.)

4. Start using it! The compiler is a GCC wrapper script found in bin/oblivcc. Example codes are in test/oblivc. A language tutorial is found here.

Most of this code was forked from the project CIL (C Intermediate Language). You can diff with the master branch to see which part was added on later.

This repository includes several example programs using Obliv-C in the test/oblivc directory. See obliv-c/test/oblivc/README.txt for details.

Please let us know if you are using Obliv-C. If you have any questions, either open an issue here on GitHub or just send me an email at [email protected].