The current HElib build, install, and regression tests suite have been built and tested on Ubuntu 20.04 and macOS Catalina >=10.15.7. Previous versions have also included Ubuntu 18.04, Fedora 33, CentOS 8.2, macOS Mojave >=10.14.6.

There are two different ways to build and install HElib. The first one will automatically download and build the GMP and NTL dependencies and pack the libraries in a relocatable folder. The second way, instead, requires the dependencies to be installed by you and available in the system.

This release of HElib has experimental support for the Intel® HEXL acceleration library for homomorphic encryption that exploits Intel® Advanced Vector Extensions 512. Instructions to enable and link to HEXL are given below.

- Please read these instructions in full to better choose the type of build that is best for you.

• pthreads
• git >= 2.27 (required to build and run the HElib test suite)

Default Linux environment:

• GNU make >= 4.2
• g++ >= 9.3.0 (recommended g++ 10.3.0)
• cmake >= 3.16

macOS environment:

• Apple clang >= 12.0.0 (available with the latest Xcode for the tested versions of macOS)
• Xcode Command Line Tools (can be installed with the command xcode-select --install in a terminal)
• cmake >= 3.20 (available from CMake or MacPorts Project and Homebrew as packages)
• GNU make >= 3.81

For HElib development:

• clang-format >= 9.0.0 (available with your linux distribution and for macOS from MacPorts Project and Homebrew as packages)

This option bundles HElib and its dependencies (NTL and GMP) in one directory which can then be moved around freely on the system. NTL and GMP will be automatically fetched and compiled. It can be installed globally (i.e. under /usr/local), which is the default option if no CMAKE_INSTALL_PREFIX is specified, but this should only be done with caution as existing versions of NTL, GMP, or HElib will be overwritten. These additional two prerequisites are required in this case:

• m4 >= 1.4.16
• patchelf >= 0.9 (if building on Linux)

Please note that if changing from library build to package build, it is safer to use a clean build directory.

1. Create a build directory, typically as a sibling of src:

cd HElib
mkdir build
cd build

2. Run the cmake configuration step, specifying that you want a package build (via -DPACKAGE_BUILD=ON) and saying where you would like the installation to be. To install in /home/alice/helib_install, for example:

cmake -DPACKAGE_BUILD=ON -DCMAKE_INSTALL_PREFIX=/home/alice/helib_install ..

Extra options can be specified here, such as enabling HElib tests with -DENABLE_TEST=ON. See later section entitled "HElib build options" for details.

3. Compile, with an optional number of threads specified (16 in this example). The output of this will be in the relocatable folder helib_pack:

make -j16

4. (optional) If step 2 was performed with -DENABLE_TEST=ON, HElib tests can be run as follows:

ctest

Detailed HElib-specific test logs can be found in Testing/Temporary/LastTest.log.

5. (optional) Run the install step, to copy the folder helib_pack to ${CMAKE_INSTALL_PREFIX} (in this example /home/alice/helib_install):

make install

of course, if the CMAKE_INSTALL_PREFIX was kept as the default /usr/local or some other system-wide path, step 5 may require sudo privileges.

This option involves building HElib on its own, linking against pre-existing dependencies (NTL and GMP) on the system. In this way, the HElib library can be moved around, but its dependencies (NTL and GMP) cannot, as they are absolute paths. For this option, you must build GMP >=6.2.1 and NTL >=11.5.1 yourself. For details on how to do this, please see the section on building dependencies later. It is assumed throughout this installation option that the environment variables $GMPDIR and $NTLDIR are set to point to the installation directories of GMP and NTL respectively.

Please note that if changing from package build to library build, it is safer to use a clean build directory.

1. Create a build directory, typically as a sibling of src:

cd HElib
mkdir build
cd build

2. Run the cmake configuration step, specifying where to find NTL and GMP. If not specified, system-wide locations such as /usr/local/lib will be searched. To install in /home/alice/helib_install, for example:

cmake -DGMP_DIR="${GMPDIR}" -DNTL_DIR="${NTLDIR}" -DCMAKE_INSTALL_PREFIX=/home/alice/helib_install ..

Extra options can be specified here, such as enabling HElib tests with -DENABLE_TEST=ON. See later section entitled "HElib build options" for details.

3. Compile, with an optional number of threads specified (16 in this example):

make -j16

4. (optional) If step 2 was performed with -DENABLE_TEST=ON, tests can be run as follows:

ctest

Detailed HElib test logs can be found in Testing/Temporary/LastTest.log.

5. Run the install step, to copy the files to ${CMAKE_INSTALL_PREFIX} (in this example /home/alice/helib_install):

make install

of course, if the CMAKE_INSTALL_PREFIX was kept as the default /usr/local or some other system-wide path, step 5 may require sudo privileges.

Many distributions come with GMP pre-installed. If not, you can install GMP as follows.

1. Download GMP from http://www.gmplib.org -- make sure that you get GMP >=6.2.0 (current version is 6.2.1).
2. Decompress and cd into the gmp directory (e.g., gmp-6.2.1).
3. GMP is compiled in the standard unix way:

      ./configure
      make
      sudo make install

This will install GMP into /usr/local by default.

NOTE: For further options when building GMP, run ./configure --help in step 3.

You can install NTL as follows:

1. Download NTL >=11.5.1 from https://libntl.org/download.html
2. Decompress and cd into the directory, e.g., ntl-11.5.1/src
3. NTL is configured, built and installed in the standard Unix way (but remember to specify the following flags to configure):

      ./configure NTL_GMP_LIP=on SHARED=on  NTL_THREADS=on NTL_THREAD_BOOST=on
      make
      sudo make install

This should install NTL into /usr/local.

NOTE: For further options when building NTL, run ./configure --help in step 3.

NOTE: if linking against a non-system GMP, pass GMP_PREFIX=<path/to/gmp> to the ./configure step.

NOTE: HElib with HEXL acceleration is only supported on the processors with AVX512DQ and AVX512-IFMA such as the 3rd generation Intel® Xeon® or the 11th generation Intel® Core®

NOTE: It is currently only possible to use HEXL with HElib when using the library build and when building HElib as a static library. i.e. -DPACKAGE_BUILD=OFF and -DBUILD_SHARED=OFF.

First you must download and build HEXL from source. Currently, HElib only works with HEXL version >= 1.2.1 Using git this would be

git clone https://github.com/intel/hexl --branch 1.2.1

Follow the instructions for HEXL installation in the README.md for all available options. Note previous versions of HEXL requires the deprecated -DENABLE_EXPORT=ON otherwise the cmake metadata for linking a cmake project is not created. Modern versions do not have this flag and the metadata is created by default. For a quick start most people will want,

cd hexl
cmake -S . -B build/ [-DCMAKE_INSTALL_PREFIX=<install-location-for-HEXL>/lib/cmake/hexl-1.2.1] 
cmake --build build -j [<parallel-jobs>]
cmake --install build

If you do not provide an optional install location for HEXL the default is /usr/local.

To enable and link HEXL in HElib, you must configure cmake for HElib with -DUSE_INTEL_HEXL=ON. If HEXL is not in the default system location or you wish to use another installation tell HElib where to find it using -DHEXL_DIR=<install-location-for-hexl>. There is no requirement to provide any HElib subprojects with the location of HEXL.

• BUILD_SHARED=ON/OFF (default is OFF): Build as a shared library. Note that building HElib (regardless of BUILD_SHARED) will fail if NTL is not built as a shared library. The default for NTL is static library, to build NTL as a shared library use ./configure SHARED=on in step 1.
• CMAKE_BUILD_TYPE: (default is RelWithDebInfo): Choose the type of build, options are: Debug, RelWithDebInfo, Release, MinSizeRel.
• CMAKE_INSTALL_PREFIX: Desired installation directory for HElib.
• ENABLE_TEST=ON/OFF (default is OFF): Enable building of tests. This will include an automatic download step for the google test framework stable release (googletest v1.10.0)
• ENABLE_THREADS=ON/OFF (default is ON): Enable threading support. This must be on if and only if NTL was built with NTL_THREADS=ON.
• PEDANTIC_BUILD=ON/OFF (default is ON): Use -Wall -Wpedantic -Wextra -Werror during build.
• HELIB_DEBUG=ON/OFF (default is OFF): Activate the debug module when building HElib (by defining the HELIB_DEBUG macro). When the debug module is active, this generates extra information used for debugging purposes. HELIB_DEBUG will propagate to programs using HElib, when using cmake. When this is enabled, programs using HElib will generate a warning during configuration. This is to remind the user that use of the debug module can cause issues, such as sigsegv, if initialized incorrectly.

• PACKAGE_DIR: Location that a package build will be installed to. Defaults to ${CMAKE_INSTALL_PREFIX}/helib_pack.
• FETCH_GMP: Whether or not to fetch and build GMP. Defaults to ON. If set to OFF, there should either exist a system-installed GMP library, or GMP_DIR should point to a valid GMP prefix.
• GMP_DIR: Prefix of the GMP library. Ignored if FETCH_GMP=ON.

• GMP_DIR: Prefix of the GMP library.
• NTL_DIR: Prefix of the NTL library.
• USE_INTEL_HEXL: Enable the Intel HEXL library.
• HEXL_DIR: Prefix of the Intel HEXL library.

After make install has been run in either option 1 or option 2, one can find the required shared library files to link against in lib and the header files in include. These can be used in the preferred way with your build system of choice.

Another, easier way is possible if you are using HElib in a cmake project.

1. Include the following line in your CMakeLists.txt:

find_package(helib)

2. Run your cmake step with -Dhelib_DIR=<helib install prefix>/share/cmake/helib.

Full working examples of cmake-based projects which uses HElib can be found in the examples directory.