Android下使用Openssl库

1.编译Openssl源代码，⽣成.so库（笔者使⽤环境为Ubuntu 18.04 amd64 桌⾯版，android_ndk_r19c 64位版）： 下载Openssl源代码，进⼊源码环境然后运⾏配置脚本，设置编译参数，开始编译：

export ANDROID_NDK=/home/gj/android-ndk-r19c

export PATH=/home/gj/android-ndk-r19c/toolchains/llvm/prebuilt/linux-x86_64/bin:$PATH ./Configure android-arm shared make SHLIB_EXT=.so -j8

　　⽣成的.so保存⼀下。如果想⽣成其他ABI架构的so，可以clean后再配置、编译：

make clean

./Configure android-arm64 shared make SHLIB_EXT=.so -j8

2.新建Android项⽬（注意要选中Native C++这个。笔者使⽤环境为Android Studio 4.0，JDK1.8，gradle 6.1.1，gradle plugin 4.0.0），复制openssl源代码⽬录下所有头⽂件（include⽬录），以及上⼀步⽣成的所有.so到Android项⽬中。

项⽬地址：

native-lib.cpp⽰例展⽰了如何使⽤openssl库进⾏RSA加解密、⽣成签名并验证签名。

代码太多，就不⼀⼀列出来内容了，可以clone代码查看内容，只列⼀下build.gradle和CMakeLists.txt主要内容：build.gradle：

android { ......

defaultConfig { ......

externalNativeBuild { cmake {

cppFlags \"-std=c++11 -frtti -fexceptions\" arguments '-DANDROID_STL=c++_shared' } ndk {

stl = \"c++_shared\"

abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a' } } } ......

sourceSets { main {

jniLibs.srcDirs = ['${PROJECT_SOURCE_DIR}/libs'] } }

packagingOptions { pickFirst '**/*.so' }

externalNativeBuild { cmake {

path \"src/main/cpp/CMakeLists.txt\" version \"3.10.2\" } }

}

　　CMakeLists.txt:

# For more information about using CMake with Android Studio, read the# documentation: https://d.android.com/studio/projects/add-native-code.htmlcmake_minimum_required(VERSION 3.4.1)

set(CMAKE_CXX_FLAGS \"${CMAKE_CXX_FLAGS} -std=gnu++11\")################################################################ import openssl library files BEGINinclude_directories(include)

set(SSL_LIB_NAME ssl)

add_library(${SSL_LIB_NAME} SHARED IMPORTED)

set_target_properties(${SSL_LIB_NAME} PROPERTIES IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/libs/${ANDROID_ABI}/lib${SSL_LIB_NAME}.so)

set(CRYPTO_LIB_NAME crypto)

add_library(${CRYPTO_LIB_NAME} SHARED IMPORTED)

set_target_properties(${CRYPTO_LIB_NAME} PROPERTIES IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/libs/${ANDROID_ABI}/lib${CRYPTO_LIB_NAME}.so)# import openssl library files END

###############################################################find_library(log-lib log)add_library(native-lib SHARED native-lib.cpp native-lib.h b64/b64.cpp b64/b64.h

b64/test_b64.cpp b64/test_b64.h rsa/rsa.cpp rsa/rsa.h

rsa/test_rsa.cpp rsa/test_rsa.h common.h)target_link_libraries( native-lib ssl crypto ${log-lib})