public String getSalt() {
        String salt = mSharedPreferences.getString(PASSWORD_SALT_PREFERENCE_KEY, null);
        if (salt == null) {
            salt = generateSalt();
            setSalt(salt);
        }
        return salt;
    }
Static method that allows to get back the current static Instance of {@link AppLockImpl}

@param context       The current context of the {@link Activity}
@param activityClass The activity extending {@link AppLockActivity}
@return The instance.
lib/src/main/java/com/github/omadahealth/lollipin/lib/managers/AppLockImpl.java