Merge pull request #11 from Commencis/documentation

Add Section about Accessing Generated Keys inside Java Class to README

README.md

@@ -11,7 +11,7 @@ The Secrets Vault Plugin employs multiple security-enhancing strategies, includi
 
 > Please remember that no client-side security measures are invincible. As a rule of thumb, **storing secrets in a mobile app is not considered best practice**. However, when there's no other option, this method is our best recommendation for concealing them.
 
-# 1) Getting started
+# 1) Getting Started
 
 To use the Secrets Vault Plugin in your Android project, follow these steps:
 
@@ -37,7 +37,7 @@ plugins {
 }
 ```
 
-# 2) Keep secrets in your project
+# 2) Keep Secrets in Your Project
 
 To keep secrets in your project, you can add them to a JSON file located in the root folder of the module where you've applied the plugin.
 Follow the format below:
@@ -81,7 +81,7 @@ secretsVault {
   - The `projectName` parameter is optional and uses the module's name where the plugin is applied by default. You can specify a different project name if needed.
   - The `version` parameter is optional. If not provided, a default CMake version will be used.
 
-# 3) Get your secret key in your app
+# 3) Get Your Secret Key in Your App
 To enable the compilation of C++ files, add these lines in the Module level `build.gradle[.kts]` :
 ```gradle
 android {
@@ -96,12 +96,53 @@ android {
 }
 ```
 
+## Access inside Kotlin
+
 Access your secret key by calling :
 ```kotlin
 val key = MainSecrets().getYourSecretKeyName()
 ```
 
-# 4) Flavor-specific secrets (Optional)
+## Access inside Java
+
+The names of the methods in the generated files (`MainSecrets.kt` & `Secrets.kt`) are replaced with dummy strings such as `a0` on the `JVM` side for extra security. This makes accessing these methods inside `Java` classes a bit tricky since those names are not "readable" and are dependent on the order in `secrets.json` file.
+
+As as solution, a helper/wrapper `Kotlin` class can be created instead of accessing these methods directly inside a `Java` class:
+
+`MySecretsHelper.kt`:
+```kotlin
+internal class MySecretsHelper {
+  val secrets = MainSecrets() // Suppose contains "external fun getYourSecretKeyName(): String" with "@JvmName("a0")" annotation.
+  val mySecret: String get() = secrets.getYourSecretKeyName()
+}
+```
+
+Inside your `Java` class, instead of doing:
+
+```java
+class MySecretsConsumer {
+  final MainSecrets secrets = new MainSecrets();
+
+  void someMethod() {
+    final String key = secrets.a0();
+    ...
+  }
+}
+```
+
+You can do:
+```java
+class MySecretsConsumer {
+  final MySecretsHelper secretsHelper = new MySecretsHelper();
+
+  void someMethod() {
+    final String key = secretsHelper.getMySecret();
+    ...
+  }
+}
+```
+
+# 4) Flavor-specific Secrets (Optional)
 If you are working on multi-flavor projects and have flavor-specific secrets, you need to pass arguments to CMake in your `build.gradle[.kts]` file. Follow the steps below:
 
 ```gradle
@@ -207,7 +248,7 @@ android {
 ```
 Remember to replace version in -Dversion=flavorName with the appropriate cmakeArgument from your JSON. The flavorName should correspond to the specific product flavor you're building for.
 
-# 6) Enhance your secrets security (Optional)
+# 6) Enhance Your Secrets' Security (Optional)
 To enhance the security of your secrets, you can create a custom encoding/decoding algorithm. The secrets will be stored in C++ and further secured by applying your custom encoding algorithm. Additionally, the decoding algorithm will be compiled, making it more challenging for an attacker to reverse-engineer and obtain your keys.
 
 Encode all values in your `secrets.json` file.