Android String Obfuscator

Hide strings easily with that lib (and script)! It uses AES/ECB/PKCS5Padding transformation to convert strings with your app's SHA1 fingerprint.

Installation

Put AndroidStringObfuscator.jar in the root of the project.

Gradle

repositories {
    jcenter()
}

dependencies {
    compile 'efraespada:androidstringobfuscator:0.4.1'
}

android.applicationVariants.all{ variant ->
    variant.mergeResources.doLast{
        println  ":" + project.name + ":initStringObfuscator"
        javaexec {
            main = "-jar";
            args = [
                  "../AndroidStringObfuscator.jar",
                  project.name,
                  variant.dirName
            ]
        }
    }
}

Setup

Initialize the library:

AndroidStringObfuscator.init(this);

Encrypt

The script will encrypt all string tags with hidden="true" as attribute.

<resources>
	<string name="hello" hidden="true">hello world!</string>
	<string name="app_name">StringObfuscator</string>
</resources>

Or encrypt strings programmatically by doing:

String encrypted = AndroidStringObfuscator.encryptString(some_string_var);

Decrypt

From resources:

String decrypted = AndroidStringObfuscator.getString(R.string.hello);

Or from encrypted variables:

String decrypted = AndroidStringObfuscator.decryptString(encrypted_var);

Sample

AndroidStringObfuscator.init(this);

// getting encrypted string resources
int stringId = R.string.hello;

String message = getString(stringId);
message += " is ";
message += AndroidStringObfuscator.getString(stringId);

// and secret
String mySecret = "lalilulelo";

message += "\n\nFor Metal Gear lovers:\n\n\"Snake, the password is " +
    AndroidStringObfuscator.encryptString(mySecret) +
    "\n\n.. or " +
    AndroidStringObfuscator.decryptString(AndroidStringObfuscator.encryptString(mySecret)) +
    "\"";

((TextView) findViewById(R.id.example)).setText(message);

Gradle Console Output Example

...
:sample:mergeDebugResources
:sample:initStringObfuscator
:sample:obfuscator-script - -----------------------------------------------------------------------------
:sample:obfuscator-script - debug variant
:sample:obfuscator-script - SHA1 fingerprint: E1:28:0C:3E:65:91:2E:21:E9:98:2B:58:80:9A:25:3A:F6:88:7D:FF
:sample:obfuscator-script - [hello world!] - [D1862D9B434D08E..]
:sample:obfuscator-script - -----------------------------------------------------------------------------
:sample:obfuscator-script - v 0.6
:sample:processDebugManifest UP-TO-DATE
...

More information

If you haven't installed Gradle before you compile:

...
:sample:obfuscator-script - Downloading https://services.gradle.org/distributions/gradle-2.14.1-all.zip
:sample:obfuscator-script - Unzipping /Users/efraespada/.gradle/wrapper/dists/gradle-2.14.1-all/8bnwg5hd3w55iofp58khbp6yv/gradle-2.14.1-all.zip to /Users/efraespada/.gradle/wrapper/dists/gradle-2.14.1-all/8bnwg5hd3w55iofp58khbp6yv
:sample:obfuscator-script - Set executable permissions for: /Users/efraespada/.gradle/wrapper/dists/gradle-2.14.1-all/8bnwg5hd3w55iofp58khbp6yv/gradle-2.14.1/bin/gradle
...

If ~/.android/debug.keystore is missing, run your app to generate that file. For non default keystore file, check your project configuration.

...
:sample:obfuscator-script - debug variant
:sample:obfuscator-script - Missing keystore
:sample:obfuscator-script - SHA1 fingerprint not detected; try params [module] [variant] [optional:sha1]
...

License

Copyright 2017 Efraín Espada

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.