find_package(OpenSSL QUIET)
if (OPENSSL_FOUND)
  set(HAVE_OPENSSL_RNG TRUE)
  if (OPENSSL_VERSION VERSION_LESS "1.1.0")
    message(STATUS "Install version >= \"1.1.0\" to enable OpenSSL support "
                   "(found version \"${OPENSSL_VERSION}\")")
  else ()
    set(DISABLE_OPENSSL FALSE CACHE BOOL "Disable OpenSSL support")
    if (NOT DISABLE_OPENSSL)
      message(STATUS "OpenSSL support enabled")
      set(HAVE_OPENSSL TRUE CACHE INTERNAL "")
    else()
      message(STATUS "OpenSSL support disabled")
      unset(HAVE_OPENSSL CACHE)
    endif()
  endif ()
else()
  message(STATUS "Install openSSL version >= \"1.1.0\" to enable OpenSSL support")
  unset(HAVE_OPENSSL_RNG)
  unset(HAVE_OPENSSL CACHE)
  set(OPENSSL_INCLUDE_DIR "")
  set(OPENSSL_LIBRARIES "")
  set(OPENSSL_CRYPTO_LIBRARY "")
endif ()

mark_as_advanced(OPENSSL_LIBRARIES OPENSSL_CRYPTO_LIBRARY)