CODEWITHSUNDEEP
javaandroidencryptionsharedpreferencesencrypted-shared-preference
angeline_1028
angeline_1028

Reputation: 51

How to implement encrypted sharepreferences

How to implement encrypted sharepreferences in my android java apps using https://developer.android.google.cn/reference/androidx/security/crypto/EncryptedSharedPreferences? I dont know how to implement it, anyone can help?

Upvotes: 4

Views: 6184

Answers (3)

Stefan
Stefan

Reputation: 71

MasterKeys.getOrCreate is deprecated, you have to use this:

public SharedPreferences getEncryptedSharedPreferences() throws GeneralSecurityException, IOException {
        MasterKey masterKeyAlias = new MasterKey.Builder(getApplicationContext())
                .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
                .build();
        SharedPreferences sharedPreferences = EncryptedSharedPreferences.create(
                getApplicationContext(),
                "secret_shared_prefs_file",
                masterKeyAlias,
                EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
                EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
        );
        return sharedPreferences;
    }

Upvotes: 0

ybloodz
ybloodz

Reputation: 317

I was using a similar code to what @Chirag wrote but after I applied new updates to my Android Studio 4.0 project, I was getting a warning that MasterKeys class is deprecated.

So I found this answer and it did the trick. Here is the code in a fragment. If you want to use it in your MainActivity, change getContext() to this

 MasterKey getMasterKey() {
    try {
        KeyGenParameterSpec spec = new KeyGenParameterSpec.Builder(
                "_androidx_security_master_key_",
                KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT)
                .setBlockModes(KeyProperties.BLOCK_MODE_GCM)
                .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
                .setKeySize(256)
                .build();

        return new MasterKey.Builder(getContext())
                .setKeyGenParameterSpec(spec)
                .build();
    } catch (Exception e) {
        Log.e(getClass().getSimpleName(), "Error on getting master key", e);
    }
    return null;
}

private SharedPreferences getEncryptedSharedPreferences() {
    try {
        return EncryptedSharedPreferences.create(
                Objects.requireNonNull(getContext()),
                "Your preference file name",
                getMasterKey(), // calling the method above for creating MasterKey
                EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
                EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
        );
    } catch (Exception e) {
        Log.e(getClass().getSimpleName(), "Error on getting encrypted shared preferences", e);
    }
    return null;
}

Then you can use the above like this:

   public void someFunction(){
        SharedPreferences sharedPreferences = getEncryptedSharedPreferences();
        //Used to add new entries and save changes
        SharedPreferences.Editor editor = sharedPreferences.edit();
        
        //To add entry to your shared preferences file
        editor.putString("Name", "Value");
        editor.putBoolean("Name", false);
        //Apply changes and commit
        editor.apply();
        editor.commit();
        
        //To clear all keys from your shared preferences file
        editor.clear().apply();
        
        //To get a value from your shared preferences file
        String returnedValue  = sharedPreferences.getString("Name", "Default value if null is returned or the key doesn't exist");
    }

Upvotes: 5

Chirag Bhuva
Chirag Bhuva

Reputation: 931

As per the documentation example, you can init EncryptedSharedPreferences like this.

public SharedPreferences getEncryptedSharedPreferences(){
   String masterKeyAlias = MasterKeys.getOrCreate(MasterKeys.AES256_GCM_SPEC);
   SharedPreferences sharedPreferences = EncryptedSharedPreferences.create(
       "secret_shared_prefs_file",
       masterKeyAlias,
       context,
       EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,
       EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM
   );
    return sharedPreferences;
}

Save Data

getEncryptedSharedPreferences().edit()
        .putString("key", value) 
        .apply()

Get Data

getEncryptedSharedPreferences().getString("key", "defaultValue");

Make sure your app API version is 23+ and you need to add this dependency

implementation "androidx.security:security-crypto:1.0.0-alpha02" //Use latest version

Upvotes: 4

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