OpenSSL bindings for Rust
Rust Shell
Latest commit 722bdb6 Jan 22, 2017 @sfackler committed on GitHub Merge pull request #550 from Keruspe/master
LibreSSL support improvements


Build Status



This README does not correspond to rust-openssl 0.7.x or 0.8.x. See here for that README.


rust-openssl depends on OpenSSL version 1.0.1 or above, or LibreSSL. Both the libraries and headers need to be present in the build environment before this crate is compiled, and some instructions of how to do this are in the sections below.


On Linux, you can typically install OpenSSL via your package manager. The headers are sometimes provided in a separate package than the runtime libraries

  • look for something like openssl-devel or libssl-dev.
# On Ubuntu
sudo apt-get install libssl-dev
# On Arch Linux
sudo pacman -S openssl
# On Fedora
sudo dnf install openssl-devel

If installation via a package manager is not possible, or if you're cross compiling to a separate target, you'll typically need to compile OpenSSL from source. That can normally be done with:

curl -O
tar xf openssl-1.1.0c.tar.gz
cd openssl-1.1.0c
export CC=...
./Configure --prefix=... linux-x86_64 -fPIC
make -j$(nproc)
make install


Although OpenSSL 0.9.8 is preinstalled on OSX this library is being phased out of OSX and this crate also does not support that version of OpenSSL. To use this crate on OSX you'll need to install OpenSSL via some alternate means, typically Homebrew:

brew install openssl

If Homebrew is installed to the default location of /usr/local, OpenSSL will be automatically detected.

Windows MSVC

On MSVC it's unfortunately not always a trivial process acquiring OpenSSL. Perhaps the easiest way to do this right now is to download precompiled binaries and install them on your system. Currently it's recommended to install the 1.1.0 (non-light) installation if you're choosing this route.

Once a precompiled binary is installed you can configure this crate to find the installation via an environment variable:

set OPENSSL_DIR=C:\OpenSSL-Win64

Note that this OpenSSL distribution does not ship with any root certificates. So to make requests to servers on the internet, you have to install them manually. Download the cacert.pem file from here, copy it somewhere safe (C:\OpenSSL-Win64\certs is a good place) and point the SSL_CERT_FILE environment variable there:

set SSL_CERT_FILE=C:\OpenSSL-Win64\certs\cacert.pem

After that, you're just a cargo build away!

Windows GNU (MinGW)

The easiest way to acquire OpenSSL when working with MinGW is to ensure you're using MSYS2 and to then execute:

# 32-bit
pacman -S mingw-w64-i686-openssl

# 64-bit
pacman -S mingw-w64-x86_64-openssl

And after that, a cargo build should be all you need!

Manual configuration

rust-openssl's build script will by default attempt to locate OpenSSL via pkg-config or other system-specific mechanisms. This will not work in some situations however, for example cross compiling or when using a copy of OpenSSL other than the normal system install.

The build script can be configured via environment variables:

  • OPENSSL_DIR - If specified, a directory that will be used to find OpenSSL installation. It's expected that under this directory the include folder has header files and a lib folder has the runtime libraries.
  • OPENSSL_LIB_DIR - If specified, a directory that will be used to find OpenSSL libraries. Overrides the lib folder implied by OPENSSL_DIR (if specified).
  • OPENSSL_INCLUDE_DIR - If specified, a directory that will be used to find OpenSSL header files. Overrides the include folder implied by OPENSSL_DIR (if specified).
  • OPENSSL_STATIC - If specified, OpenSSL libraries will be statically rather than dynamically linked.

If OPENSSL_DIR is specified, then the build script will skip the pkg-config step.