diff --git a/CMakeLists.txt b/CMakeLists.txt
index b442be6..e27e459 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,13 +1,22 @@
 cmake_minimum_required (VERSION 3.5)
 if (NOT DEFINED CMAKE_CXX_COMPILER)
-  set(CMAKE_CXX_COMPILER /usr/bin/clang++-6.0)
+  set(CMAKE_CXX_COMPILER /usr/bin/clang++)
 endif()
 
 project(StarkwareCryptoLib VERSION 0.1.0 LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 17)
+
+include(FetchContent)
+FetchContent_Declare(
+  googletest
+  URL https://github.com/google/googletest/archive/609281088cfefc76f9d0ce82e1ff6c30cc3591e5.zip
+)
+# For Windows: Prevent overriding the parent project's compiler/linker settings
+set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+FetchContent_MakeAvailable(googletest)
+
 include(CTest)
-# Basic setup for gtest
-find_package(GTest REQUIRED)
-include_directories(${GTEST_INCLUDE_DIRS})
 enable_testing()
 include_directories("${CMAKE_SOURCE_DIR}/src")
 
diff --git a/presubmit.sh b/presubmit.sh
index 6e69dcc..d45960e 100755
--- a/presubmit.sh
+++ b/presubmit.sh
@@ -2,11 +2,11 @@
 
 set -e
 
-(cd src/starkware/crypto/ffi/js; npm install)
+(cd src/starkware/crypto/ffi/js; npm install --no-package-lock)
 
 mkdir -p build/Release
 (cd build/Release; cmake -DCMAKE_BUILD_TYPE=Release ../..)
 make -C build/Release
 CTEST_OUTPUT_ON_FAILURE=1 make -C build/Release test
-clang-tidy-6.0 -header-filter=src/starkware -p=build/Release $(find src/starkware -name "*.cc" | grep -v node_modules)
+clang-tidy -header-filter=src/starkware -p=build/Release $(find src/starkware -name "*.cc" | grep -v node_modules)
 cpplint --extensions=cc,h $(find src/starkware | grep -v node_modules | grep -E '\.(cc|h)$')
diff --git a/src/starkware/algebra/CMakeLists.txt b/src/starkware/algebra/CMakeLists.txt
index 8046434..0b5eaef 100644
--- a/src/starkware/algebra/CMakeLists.txt
+++ b/src/starkware/algebra/CMakeLists.txt
@@ -1,7 +1,7 @@
 add_library(algebra prime_field_element.cc)
 
 add_executable(big_int_test big_int_test.cc)
-target_link_libraries(big_int_test gtest gtest_main pthread)
+target_link_libraries(big_int_test gtest gtest_main gmock pthread)
 add_test(big_int_test big_int_test)
 
 add_executable(prime_field_element_test prime_field_element_test.cc)
@@ -9,9 +9,9 @@ target_link_libraries(prime_field_element_test algebra gtest gtest_main pthread)
 add_test(prime_field_element_test prime_field_element_test)
 
 add_executable(fraction_field_element_test fraction_field_element_test.cc)
-target_link_libraries(fraction_field_element_test algebra gtest gtest_main pthread)
+target_link_libraries(fraction_field_element_test algebra gtest gtest_main gmock pthread)
 add_test(fraction_field_element_test fraction_field_element_test)
 
 add_executable(elliptic_curve_test elliptic_curve_test.cc)
-target_link_libraries(elliptic_curve_test algebra gtest gtest_main pthread)
+target_link_libraries(elliptic_curve_test algebra gtest gtest_main gmock pthread)
 add_test(elliptic_curve_test elliptic_curve_test)
diff --git a/src/starkware/crypto/CMakeLists.txt b/src/starkware/crypto/CMakeLists.txt
index 7ee5ecc..93cfa25 100644
--- a/src/starkware/crypto/CMakeLists.txt
+++ b/src/starkware/crypto/CMakeLists.txt
@@ -4,7 +4,7 @@ add_library(crypto elliptic_curve_constants.cc pedersen_hash.cc ecdsa.cc)
 target_link_libraries(crypto algebra)
 
 add_executable(elliptic_curve_constants_test elliptic_curve_constants_test.cc)
-target_link_libraries(elliptic_curve_constants_test gtest crypto gtest_main pthread)
+target_link_libraries(elliptic_curve_constants_test gtest crypto gtest_main gmock pthread)
 add_test(elliptic_curve_constants_test elliptic_curve_constants_test)
 
 add_executable(pedersen_hash_test pedersen_hash_test.cc)
diff --git a/src/starkware/crypto/ffi/js/CMakeLists.txt b/src/starkware/crypto/ffi/js/CMakeLists.txt
index 689a5b5..e333852 100644
--- a/src/starkware/crypto/ffi/js/CMakeLists.txt
+++ b/src/starkware/crypto/ffi/js/CMakeLists.txt
@@ -1,14 +1,14 @@
 add_custom_command(
-    OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/libcrypto_c_exports.so
+    OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/libcrypto
     COMMAND
         ${CMAKE_COMMAND} -E copy
-        ${CMAKE_CURRENT_BINARY_DIR}/../libcrypto_c_exports.so
-        ${CMAKE_CURRENT_SOURCE_DIR}/libcrypto_c_exports.so
+        ${CMAKE_CURRENT_BINARY_DIR}/../libcrypto_c_exports.*
+        ${CMAKE_CURRENT_SOURCE_DIR}
     DEPENDS crypto_c_exports
 )
 
 add_custom_target(js_test ALL
-    DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/libcrypto_c_exports.so
+    DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/libcrypto
 )
 
 add_test(
diff --git a/src/starkware/crypto/ffi/js/package.json b/src/starkware/crypto/ffi/js/package.json
index 8d4bf3a..d04f3c8 100644
--- a/src/starkware/crypto/ffi/js/package.json
+++ b/src/starkware/crypto/ffi/js/package.json
@@ -15,7 +15,7 @@
   "license": "Apache-2.0",
   "dependencies": {
     "bigint-buffer": "^1.1.5",
-    "bn": "^1.0.5",
+    "bn.js": "^5.2.0",
     "ffi-napi": "^3.1.0"
   },
   "devDependencies": {
diff --git a/src/starkware/crypto/ffi/portable_endian.h b/src/starkware/crypto/ffi/portable_endian.h
new file mode 100644
index 0000000..178020a
--- /dev/null
+++ b/src/starkware/crypto/ffi/portable_endian.h
@@ -0,0 +1,112 @@
+#ifndef STARKWARE_CRYPTO_FFI_PORTABLE_ENDIAN_H_
+#define STARKWARE_CRYPTO_FFI_PORTABLE_ENDIAN_H_
+
+#if (defined(_WIN16) || defined(_WIN32) || defined(_WIN64)) && !defined(__WINDOWS__)
+
+#   define __WINDOWS__
+
+#endif
+
+#if defined(__linux__) || defined(__CYGWIN__)
+
+#   include <endian.h>
+
+#elif defined(__APPLE__)
+
+#   include <libkern/OSByteOrder.h>
+
+#   define htobe16(x) OSSwapHostToBigInt16(x)
+#   define htole16(x) OSSwapHostToLittleInt16(x)
+#   define be16toh(x) OSSwapBigToHostInt16(x)
+#   define le16toh(x) OSSwapLittleToHostInt16(x)
+
+#   define htobe32(x) OSSwapHostToBigInt32(x)
+#   define htole32(x) OSSwapHostToLittleInt32(x)
+#   define be32toh(x) OSSwapBigToHostInt32(x)
+#   define le32toh(x) OSSwapLittleToHostInt32(x)
+
+#   define htobe64(x) OSSwapHostToBigInt64(x)
+#   define htole64(x) OSSwapHostToLittleInt64(x)
+#   define be64toh(x) OSSwapBigToHostInt64(x)
+#   define le64toh(x) OSSwapLittleToHostInt64(x)
+
+#   define __BYTE_ORDER    BYTE_ORDER
+#   define __BIG_ENDIAN    BIG_ENDIAN
+#   define __LITTLE_ENDIAN LITTLE_ENDIAN
+#   define __PDP_ENDIAN    PDP_ENDIAN
+
+#elif defined(__OpenBSD__)
+
+#   include <sys/endian.h>
+
+#elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
+
+#   include <sys/endian.h>
+
+#   define be16toh(x) betoh16(x)
+#   define le16toh(x) letoh16(x)
+
+#   define be32toh(x) betoh32(x)
+#   define le32toh(x) letoh32(x)
+
+#   define be64toh(x) betoh64(x)
+#   define le64toh(x) letoh64(x)
+
+#elif defined(__WINDOWS__)
+
+#   include <winsock2.h>
+#   include <sys/param.h>
+
+#   if BYTE_ORDER == LITTLE_ENDIAN
+
+#      define htobe16(x) htons(x)
+#      define htole16(x) (x)
+#      define be16toh(x) ntohs(x)
+#      define le16toh(x) (x)
+
+#      define htobe32(x) htonl(x)
+#      define htole32(x) (x)
+#      define be32toh(x) ntohl(x)
+#      define le32toh(x) (x)
+
+#      define htobe64(x) htonll(x)
+#      define htole64(x) (x)
+#      define be64toh(x) ntohll(x)
+#      define le64toh(x) (x)
+
+#   elif BYTE_ORDER == BIG_ENDIAN
+
+      /* that would be xbox 360 */
+#      define htobe16(x) (x)
+#      define htole16(x) __builtin_bswap16(x)
+#      define be16toh(x) (x)
+#      define le16toh(x) __builtin_bswap16(x)
+
+#      define htobe32(x) (x)
+#      define htole32(x) __builtin_bswap32(x)
+#      define be32toh(x) (x)
+#      define le32toh(x) __builtin_bswap32(x)
+
+#      define htobe64(x) (x)
+#      define htole64(x) __builtin_bswap64(x)
+#      define be64toh(x) (x)
+#      define le64toh(x) __builtin_bswap64(x)
+
+#   else
+
+#      error byte order not supported
+
+#   endif
+
+#   define __BYTE_ORDER    BYTE_ORDER
+#   define __BIG_ENDIAN    BIG_ENDIAN
+#   define __LITTLE_ENDIAN LITTLE_ENDIAN
+#   define __PDP_ENDIAN    PDP_ENDIAN
+
+#else
+
+#   error platform not supported
+
+#endif
+
+#endif  // STARKWARE_CRYPTO_FFI_PORTABLE_ENDIAN_H_
diff --git a/src/starkware/crypto/ffi/utils.cc b/src/starkware/crypto/ffi/utils.cc
index 9a1e71c..49b9292 100644
--- a/src/starkware/crypto/ffi/utils.cc
+++ b/src/starkware/crypto/ffi/utils.cc
@@ -1,8 +1,8 @@
-#include <endian.h>
 #include <algorithm>
 #include <cstring>
 
 #include "starkware/crypto/ffi/utils.h"
+#include "starkware/crypto/ffi/portable_endian.h"
 
 namespace starkware {
 
diff --git a/src/starkware/starkex/CMakeLists.txt b/src/starkware/starkex/CMakeLists.txt
index 435cb75..7e744aa 100644
--- a/src/starkware/starkex/CMakeLists.txt
+++ b/src/starkware/starkex/CMakeLists.txt
@@ -2,5 +2,5 @@ add_library(starkex order.cc)
 target_link_libraries(starkex crypto)
 
 add_executable(order_test order_test.cc)
-target_link_libraries(order_test starkex gtest gtest_main pthread)
+target_link_libraries(order_test starkex gtest gtest_main gmock pthread)
 add_test(order_test order_test)
diff --git a/src/starkware/utils/CMakeLists.txt b/src/starkware/utils/CMakeLists.txt
index 0b50e36..e0afe21 100644
--- a/src/starkware/utils/CMakeLists.txt
+++ b/src/starkware/utils/CMakeLists.txt
@@ -1,7 +1,7 @@
 add_executable(math_test math_test.cc)
-target_link_libraries(math_test gtest gtest_main pthread)
+target_link_libraries(math_test gtest gtest_main gmock pthread)
 add_test(math_test math_test)
 
 add_executable(prng_test prng_test.cc)
-target_link_libraries(prng_test gtest gtest_main pthread)
+target_link_libraries(prng_test gtest gtest_main gmock pthread)
 add_test(prng_test prng_test)