First of all, if this repository or content violate any law or rules from the original owner, please let me know in the GitHub Issue section. I will take down this repository as soon as possible.

Quick Use

• Clone or download this repository and use the pre-build files inside android-build follow How To Use section. If you prefer latest build, please proceed to the following guide. Thank you.

Build CPP OpenSSL for Android

• Clone OpenSSL repository from GitHub: https://github.com/openssl/openssl.git

git clone https://github.com/openssl/openssl.git

• Navigate to openssl folder that you already cloned and create android-build.sh shell script file, put below code in and save. -D__ANDROID_API__=21 is minSdkVersion currently set to 21. You can change base on the project you build for:

#!/bin/bash

# Exit immediately if a command exits with a non-zero status
set -euo pipefail

# Ensure ANDROID_NDK_ROOT is set
if [ -z "${ANDROID_NDK_ROOT:-}" ]; then
    echo "Error: ANDROID_NDK_ROOT environment variable is not set."
    echo "Please set it to your Android NDK path (e.g. export ANDROID_NDK_ROOT=/path/to/ndk)"
    exit 1
fi

# Detect host OS to locate the prebuilt NDK toolchain
HOST_OS=$(uname -s | tr '[:upper:]' '[:lower:]')
case "$HOST_OS" in
    darwin)
        NDK_HOST="darwin-x86_64"
        ;;
    linux)
        NDK_HOST="linux-x86_64"
        ;;
    *)
        echo "Error: Unsupported host OS '$HOST_OS'"
        exit 1
        ;;
esac

TOOLCHAIN_BIN="$ANDROID_NDK_ROOT/toolchains/llvm/prebuilt/$NDK_HOST/bin"
if [ ! -d "$TOOLCHAIN_BIN" ]; then
    echo "Error: NDK toolchain bin directory not found at: $TOOLCHAIN_BIN"
    exit 1
fi

# Add the NDK toolchain to the PATH so Configure can find the compiler and binutils
export PATH="$TOOLCHAIN_BIN:$PATH"

# Determine the number of CPU cores for parallel make
NUM_CORES=1
if [ "$HOST_OS" = "darwin" ]; then
    NUM_CORES=$(sysctl -n hw.ncpu 2>/dev/null || echo 1)
elif [ "$HOST_OS" = "linux" ]; then
    NUM_CORES=$(nproc 2>/dev/null || echo 1)
fi

build_one() {
    local arch=$1
    local abi=$2

    echo "=========================================================="
    echo "Building OpenSSL for $arch ($abi)"
    echo "=========================================================="

    # Only clean if a Makefile exists from a previous config
    if [ -f Makefile ]; then
        make clean
    fi

    # Optimization compiler flags
    # -Os: optimize for size
    # -fdata-sections, -ffunction-sections: allow dead code stripping when linking
    # -fvisibility=hidden: hide internal symbols to prevent export bloat
    # -g0: omit debug symbols to minimize file size
    local cflags="-Os -fdata-sections -ffunction-sections -fvisibility=hidden -g0"

    # Disable unused, deprecated, insecure, and heavyweight features to optimize size
    local disabled_features="no-shared no-asm no-engine no-comp no-tests no-ui-console \
                             no-legacy no-deprecated no-quic no-filenames \
                             no-md2 no-md4 no-mdc2 no-rc2 no-rc4 no-rc5 no-idea no-seed no-bf no-cast no-camellia no-whirlpool \
                             no-des no-dsa no-srp no-scrypt no-argon2 no-ts no-cms no-nextprotoneg no-ocsp \
                             no-ssl3 no-tls1 no-tls1-method no-tls1_1 no-tls1_1-method no-dtls \
                             no-aria no-blake2 no-chacha no-poly1305 no-sm2 no-sm3 no-sm4 \
                             no-ml-dsa no-ml-kem no-lms"

    # Configure the build:
    # --libdir=lib: Force lib directory name (avoiding lib64 on 64-bit architectures)
    # -D__ANDROID_API__=21: Set baseline Android API level 21
    ./Configure "$arch" \
        -D__ANDROID_API__=21 \
        --libdir=lib \
        $disabled_features \
        $cflags \
        -fPIC \
        --prefix="$(pwd)/android-build/$abi"

    # Compile using parallel cores
    make -j"$NUM_CORES"
    
    # Install software components only (skips documentation)
    make install_sw

    # Move static libraries to the top level of the build directory
    local dest_dir="$(pwd)/android-build/$abi"
    mv "$dest_dir/lib/libssl.a" "$dest_dir/"
    mv "$dest_dir/lib/libcrypto.a" "$dest_dir/"

    # Strip debugging symbols and unneeded symbols from the static libraries
    if command -v llvm-strip >/dev/null 2>&1; then
        echo "Stripping static libraries..."
        llvm-strip -g "$dest_dir/libssl.a"
        llvm-strip -g "$dest_dir/libcrypto.a"
    else
        echo "Warning: llvm-strip not found. Libraries were not stripped."
    fi

    # Clean up installation folders to leave only include/ and the static libraries
    rm -rf "$dest_dir/bin"
    rm -rf "$dest_dir/lib"
    rm -rf "$dest_dir/share"
}

# Build for target architectures
build_one "android-arm64" "arm64-v8a"
build_one "android-arm" "armeabi-v7a"

# Optional: uncomment to also build for emulators / x86 targets
# build_one "android-x86_64" "x86_64"
# build_one "android-x86" "x86"

if [ -f Makefile ]; then
    make clean
fi

echo "========== ALL DONE =========="

• Run below command to grand execute permission to the script file you've just created:

chmod +x build_openssl.sh

• Now run the script and wait until it finish. This will take a while depends on your machine performance:

./android-build.sh

• When all build complete, you can see folder named android-build inside current openssl directory we're working on.

How To Use

• Copy all the content inside android-build folder and place inside your project's cpp folder. I recommend to put under cpp → libs → openssl folder so it's easy to copy below CMakeList without making any change. Directory look like this:

cpp/
└── libs/
    └── openssl/
        ├── arm64-v8a/
        │   ├── include/
        │   │   └── openssl/
        │   ├── libcrypto.a
        │   └── libssl.a
        ├── armeabi-v7a/
        │   ├── include/
        │   │   └── openssl/
        │   ├── libcrypto.a
        │   └── libssl.a
        ├── x86/
        │   ├── include/
        │   │   └── openssl/
        │   ├── libcrypto.a
        │   └── libssl.a
        └── x86_64/
            ├── include/
            │   └── openssl/
            ├── libcrypto.a
            └── libssl.a
├── CMakeLists.txt
└── native-lib.cpp

• Add these below line to your CMakeLists.txt and make sure it above target_link_libraries. If your main lib is not native-lib.cpp you can update it according to your project naming:

# OpenSSL Configuration ========================================================
# Hide symbols to prevent conflicts in the final SDK
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden")

# Path to headers
target_include_directories(native-lib PRIVATE ${CMAKE_SOURCE_DIR}/libs/openssl/${ANDROID_ABI}/include)

# Import libssl
add_library(ssl STATIC IMPORTED)
set_target_properties(ssl PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/libs/openssl/${ANDROID_ABI}/libssl.a)

# Import libcrypto
add_library(crypto STATIC IMPORTED)
set_target_properties(crypto PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/libs/openssl/${ANDROID_ABI}/libcrypto.a)
# ==============================================================================

• Finally, add ssl and crypto to target_link_libraries. Make sure that ssl is before crypto and those 2 are at the end of target_link_libraries. Here is the example of what it looks like:

target_link_libraries(native-lib PRIVATE ${log-lib} android ssl crypto)

• I'll drop a snipped code to my CMakeLists.txt to show you what is look like:

cmake_minimum_required(VERSION 3.18.1)
project(CPP-Android-OpenSSL)
add_library(native-lib SHARED native-lib.cpp)
find_library(log-lib log)

# OpenSSL Configuration ========================================================
# Hide symbols to prevent conflicts in the final SDK
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden")

# Path to headers
target_include_directories(native-lib PRIVATE ${CMAKE_SOURCE_DIR}/libs/openssl/${ANDROID_ABI}/include)

# Import libssl
add_library(ssl STATIC IMPORTED)
set_target_properties(ssl PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/libs/openssl/${ANDROID_ABI}/libssl.a)

# Import libcrypto
add_library(crypto STATIC IMPORTED)
set_target_properties(crypto PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/libs/openssl/${ANDROID_ABI}/libcrypto.a)
# ==============================================================================

target_link_libraries(native-lib PRIVATE ${log-lib} android ssl crypto)

NOTE

• The library size is over 50MB and almost 600 items during I make this document. I would suggest you to add the main openssl folder to .gitignore so you don't push all this files to your repository.