安全加密C語言庫OpenSSL阐滩，在Android中服務(wù)器和客戶端之間的簽名驗(yàn)證和數(shù)據(jù)加密通信等。

OpenSSL系列文章：

一砸西、Android CMake輕松實(shí)現(xiàn)基于OpenSSL的HmacSHA1簽名

二叶眉、Android CMake輕松實(shí)現(xiàn)基于OpenSSL的SHA(1-512)簽名

三、Android CMake輕松實(shí)現(xiàn)基于OpenSSL的MD5信息摘要&異或加解密

四芹枷、Android CMake輕松實(shí)現(xiàn)基于OpenSSL的AES加解密

五衅疙、Android CMake輕松實(shí)現(xiàn)基于OpenSSL的RSA加解密

六、Android CMake輕松實(shí)現(xiàn)基于OpenSSL的RSA簽名和驗(yàn)證

七鸳慈、在Retrofit的基礎(chǔ)上結(jié)合OpenSSL實(shí)現(xiàn)服務(wù)器和客戶端之間數(shù)據(jù)加密通信

最近有這么一個需求饱溢，要對接口進(jìn)行簽名驗(yàn)證以防止被刷。開始想到了在Java中實(shí)現(xiàn)HmacSHA1簽名走芋，但由于Java代碼較容易反編譯直接獲取秘鑰绩郎，而否定了這個方案。為了解決這個問題翁逞，把實(shí)現(xiàn)簽名的邏輯代碼用C/C++來編寫肋杖，編譯成xxx.so庫，大大提高了反編譯的門檻挖函，從而降低了被反編譯的風(fēng)險状植。

在C/C++中要實(shí)現(xiàn)HmacSHA1簽名，只有依賴一個很出名的C語言中常用的加解密庫OpenSSL。什么是OpenSSL請自行百度津畸，隨便搜都是一大堆振定。難點(diǎn)在于在Android中進(jìn)行Jni開發(fā)，在C/C++文件中要調(diào)用第三方OpenSSL的xxx.so庫肉拓，那怎樣才能把OpenSSL的xxx.so庫引入我們的C/C++文件中呢后频？換句話說就是最終我們的C/C++文件會被編譯成一個.so庫，就叫l(wèi)ibsignature.so吧暖途！而這個庫又引用了第三方xxx.so庫卑惜。不過不用擔(dān)心，自從Android支持CMake后丧肴，一切都變得簡單了残揉。網(wǎng)絡(luò)上也有很多博客，也有很多代碼片段芋浮，但是對于初學(xué)者來說，根本不知道那是什么玩意兒壳快！所以我想寫細(xì)一點(diǎn)纸巷。

一：新建項(xiàng)目
如下圖勾選include C++ support，然后一路next眶痰，直到finish瘤旨。

新建NDK工程.png

二：編譯OpenSSL源碼得到.so庫
OpenSSL源碼:github上搜索關(guān)鍵字【OpenSSL for Android】下載并編譯，拷貝所有.so到app/alley/lib/目錄下竖伯，拷貝OpenSSL所有頭文件到app/alley/include/openssl/目錄下存哲。

alley文件目錄.png

三：gradle配置

#app目錄下build.gradle
apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"
    defaultConfig {
        applicationId "com.alley.openssl"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        externalNativeBuild {
            cmake {
                cppFlags "-std=c++11 -frtti -fexceptions"
                //目標(biāo)平臺，若需要更多平臺的請自行配置
                abiFilters 'armeabi'
            }
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    sourceSets {
        main {
            //第三方.so庫路徑
            jniLibs.srcDirs = ['E:\\AndroidSpace\\OpenSSL\\app\\alley\\lib']
        }
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha8'
    testCompile 'junit:junit:4.12'
}

四：CMakeLists腳本
CMakeLists腳本語法請自行查閱

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

# Sets the minimum version of CMake required to build the native library.

cmake_minimum_required(VERSION 3.4.1)
#C++編譯
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")

#配置加載頭文件
include_directories(E:/AndroidSpace/OpenSSL/app/alley/include)

#動態(tài)方式加載
add_library(openssl SHARED IMPORTED )
add_library(ssl SHARED IMPORTED )
#引入第三方.so庫
set_target_properties(openssl PROPERTIES IMPORTED_LOCATION E:/AndroidSpace/OpenSSL/app/alley/lib/${ANDROID_ABI}/libcrypto.so)
set_target_properties(ssl PROPERTIES IMPORTED_LOCATION E:/AndroidSpace/OpenSSL/app/alley/lib/${ANDROID_ABI}/libssl.so)

# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.

add_library( # Sets the name of the library.
             signature

             # Sets the library as a shared library.
             SHARED

             # Provides a relative path to your source file(s).
             src/main/cpp/signature.cpp )

# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.

find_library( # Sets the name of the path variable.
              log-lib

              # Specifies the name of the NDK library that
              # you want CMake to locate.
              log )

# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.

target_link_libraries( # Specifies the target library.
                       signature
                       openssl
                       ssl
                       android

                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

五：加解密
HmacSHA1算法得到簽名結(jié)果為十六進(jìn)制數(shù)七婴。在本項(xiàng)目中對其進(jìn)行Base64編碼祟偷，發(fā)現(xiàn)編碼結(jié)果為28位的，這和用Java代碼實(shí)現(xiàn)的完全不同（Java實(shí)現(xiàn)的是56位）打厘，在線base64編碼測試結(jié)果也為56位修肠。原因是什么呢？
待編碼數(shù)據(jù)是按照** %02x 格式輸出的值户盯，然后用這個值再次進(jìn)行base64編碼嵌施。在這里解釋一下 %02x：按照十六進(jìn)制進(jìn)行數(shù)據(jù)輸出，不足兩位莽鸭，則在之前補(bǔ)0吗伤，否則按實(shí)際數(shù)據(jù)輸出。 所以用到了sprintf(char *, const char *, ...)和strcat(char , const char )函數(shù)硫眨，這才是重點(diǎn)啊足淆，不太容易發(fā)現(xiàn)。在開發(fā)過程中注意C++函數(shù)名與native方法的關(guān)系。將最后編譯生成的libsignature.so拷貝你的項(xiàng)目中就可以使用了缸浦。秘鑰自己設(shè)定夕冲，注意不要泄露了。更多詳情請閱讀源碼裂逐。

#include <jni.h>
#include <string>
#include <Android/log.h>
#include <openssl/hmac.h>


#define TAG "JNI"
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO, TAG, __VA_ARGS__)
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, TAG, __VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR, TAG, __VA_ARGS__)

extern "C"
JNIEXPORT jbyteArray JNICALL
Java_com_alley_openssl_util_JniUtils_getSignature(JNIEnv *env, jobject instance, jbyteArray value_) {
    const char *key = "5fd6s4gs8f7s1dfv23sdf4ag65rg4arhb4fb1f54bgf5gbvf1534as";
    LOGI("HmacSHA1->準(zhǔn)備獲取待加密數(shù)據(jù)");
    jbyte *value = env->GetByteArrayElements(value_, NULL);
    LOGI("HmacSHA1->準(zhǔn)備計(jì)算待加密數(shù)據(jù)長度");
    size_t value_Len = env->GetArrayLength(value_);

    unsigned int result_len;
    unsigned char result[EVP_MAX_MD_SIZE];
    char buff[EVP_MAX_MD_SIZE];
    char hex[EVP_MAX_MD_SIZE];

    LOGI("HmacSHA1->準(zhǔn)備進(jìn)行加密計(jì)算");
    HMAC(EVP_sha1(), key, strlen(key), (unsigned char *) value, value_Len, result, &result_len);
    LOGI("HmacSHA1->加密計(jì)算結(jié)束");

    strcpy(hex, "");
    for (int i = 0; i != result_len; i++) {
        sprintf(buff, "%02x", result[i]);
        strcat(hex, buff);
    }
    LOGI("HmacSHA1->");
    LOGI("%s", hex);

    env->ReleaseByteArrayElements(value_, value, 0);
    LOGI("HmacSHA1->jni釋放數(shù)據(jù)結(jié)束");
    jbyteArray signature = env->NewByteArray(strlen(hex));
    env->SetByteArrayRegion(signature, 0, strlen(hex), (jbyte *) hex);
    LOGI("HmacSHA1->準(zhǔn)備以ByteArray格式返回數(shù)據(jù)");
    return signature;
}

六：測試
待簽名數(shù)據(jù)：Android CMake輕松實(shí)現(xiàn)基于OpenSSL的HmacSHA1簽名
秘鑰：5fd6s4gs8f7s1dfv23sdf4ag65rg4arhb4fb1f54bgf5gbvf1534as
在線簽名校驗(yàn)：http://tool.oschina.net/encrypt?type=2歹鱼，經(jīng)測試代碼簽名和在線簽名結(jié)果相同。

下載代碼運(yùn)行卜高，在控制臺中輸入“body”弥姻，將看到所有調(diào)試信息。歡迎star掺涛，fork庭敦，轉(zhuǎn)載。

源碼：https://github.com/GitPhoenix/OpenSSL