Secure your API Using NDK

NDK means Native Development Kit this is kind of kit you can use C and C++ code using this Development kit

so let’s start our steps how can you use NDK and secure your API from other person so let’s start

Step-1

Click on SDK Manager and open SDK Manager From Screen shot below

Step-2

then after make sure that you have 2 SDK Tools which are NDK(Side by side)& CMake if you haven’t that then install that SDK Tools

Step-3

Right Click on Main and create new directory Named jni (JAVA NATIVE INTERFACE) we will store our c files in this folder so we can use that

Step-4

Create Android.mk file in jni folder and paste this code into Android.mk

==>

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := keys
LOCAL_SRC_FILES := keys.c

include $(BUILD_SHARED_LIBRARY)

≤==

Step-5

Create Application.mk file in same directory and paste this code

==>

APP_ABI := all

≤==

Step-6

Create one more file name keys.c file and paste this code into your keys.c file

so I create one method here which is Java_com_example_secureapi_ActivityName_MethodName

so basically this is package name of your application com.example.secureapi and (_)underscore replace with (.)dot and then after ActivityName if you want your key in MainActivity then write Java_com_example_secureapi_MainActivity_MethodName and then after Method Name you can get your api key using MethodName if my Method Name is GetApi then my Function name will be Java_com_example_secureapi_MainActivity_GetApi

==>

#include <jni.h>

JNIEXPORT jstring JNICALL
Java_com_example_secureapi_ActivityName_MethodName(JNIEnv *env, jobject instance) {

return (*env)-> NewStringUTF(env, “TmF0aXZlNWVjcmV0UEBzc3cwcmQx”);
}

≤==

after completing this steps your file structure will be

File Structure

ok So now Done from NDK Side

Step-7

Last step Go to buld.gradle(Module.secureapi.app)

then add this code

==>

ndkVersion ‘23.0.7599858’

externalNativeBuild {
ndkBuild {
path ‘src/main/jni/Android.mk’//path of Android.mk file
}
}

≤==

check ndk version from this path : : C:\Users\USER\AppData\Local\Android\Sdk\ndk

Step-8

So Finally We done our code so jump on Android Code

==> By Using System.loadLibrary(“keys”); you can load your c file in android then after using public native String GetApi(); this method return one String API key you can use it as you want to use

Thank you

Note :: if you get error after doing this then retry step-7 and try…