sealsharp - C# bindings and API for SEAL

Introduction

SEAL is an open-source library from Microsoft Research (code) for performing homomorphic encryption - a way of computing with encrypted data without first having to decrypt it.

sealsharp is a user-friendly .NET API for SEAL. Computations are represented using C# LINQ Expressions to form an abstract syntax tree. Sealsharp then analyzes and compiles this expression tree into calls to the underlying SEAL library.

Example

Define expression:

Expression<Func<long, long, long>> computation = (x, y) => x + (x * y);

Evaluate expression:

Ciphertext encrypted_result = evaluator.CompileAndRun (computation, relin_keys, encrypted_x, encrypted_y);

A full example is in the sealsharp-example directory.

Status

The project is an early proof of concept.

At the moment we have C# bindings for only a small subset of the full SEAL API. More functions and classes are easy to add, but it is work that has not been done yet.

The SEAL Linq Expressions high-level API also only covers a small subset of the possible expressions that you could write.

PRs welcome!

Building

Dependencies and prerequisites

Install cmake (OSX: brew install cmake) and Mono. You will also need a C++ compiler.

Building

1. Make sure to initialize submodules when you first clone or when you pull changes.

   git submodule update --init --recursive
   

2. Run prepare.sh to build SEAL and install it into ./build/install

   ./prepare.sh
   

   The above will also compile the SEAL examples into ./external/SEAL/bin/sealexamples

3. Compile the seal-c C bindings

   ./seal-c.sh
   

   This will leave a shared library in ./build/install/lib/ named libseal-c.so or libseal-c.dylib

4. Build the C# bindings and example

   msbuild /t:Restore
   msbuild
   

5. Run the C# example

   mono build/sealsharp-example/bin/Debug/net462/sealsharp-example.exe
   

The last two steps could also be done from Visual Studio by opening sealsharp.sln and building from the menus