// VULNERABLE IMPLEMENTATION: Biometric authentication with CryptoObject but without actually using itpublicclassMisusedCryptoObjectAuthenticator{privatestaticfinalStringENCRYPTED_DATA_KEY="encrypted_data";privateSharedPreferencespreferences;privateCiphercipher;privateSecretKeysecretKey;publicMisusedCryptoObjectAuthenticator(Contextcontext){this.preferences=context.getSharedPreferences("app_prefs",Context.MODE_PRIVATE);try{// Initialize crypto componentsKeyGeneratorkeyGenerator=KeyGenerator.getInstance("AES");keyGenerator.init(256);secretKey=keyGenerator.generateKey();cipher=Cipher.getInstance("AES/GCM/NoPadding");cipher.init(Cipher.ENCRYPT_MODE,secretKey);}catch(Exceptione){e.printStackTrace();}}publicvoidauthenticateUser(finalAuthenticationCallbackcallback){try{// We create a CryptoObject and pass it to the biometric promptBiometricPrompt.CryptoObjectcryptoObject=newBiometricPrompt.CryptoObject(cipher);BiometricPromptbiometricPrompt=newBiometricPrompt(activity,executor,newBiometricPrompt.AuthenticationCallback(){@OverridepublicvoidonAuthenticationSucceeded(BiometricPrompt.AuthenticationResultresult){// VULNERABILITY: We have the cryptoObject but don't use it!// Instead, we just set a flag or retrieve data directly// The CryptoObject from the result is ignoredBiometricPrompt.CryptoObjectcryptoResult=result.getCryptoObject();// Simply set authentication flag without using the CryptoObjectsetAuthenticated(true);callback.onSuccess();}@OverridepublicvoidonAuthenticationFailed(){callback.onFailure("Authentication failed");}});// We pass the cryptoObject to authenticatebiometricPrompt.authenticate(promptInfo,cryptoObject);}catch(Exceptione){callback.onFailure("Error: "+e.getMessage());}}privatevoidsetAuthenticated(booleanauthenticated){preferences.edit().putBoolean("is_authenticated",authenticated).apply();}// VULNERABILITY: This method retrieves sensitive data without requiring the// cryptoObject that was used during authenticationpublicStringgetSensitiveData(){// Simply checks a boolean flag instead of using crypto bindingif(preferences.getBoolean("is_authenticated",false)){// Get data without using the CryptoObject for decryptionStringencryptedData=preferences.getString(ENCRYPTED_DATA_KEY,null);// We manually decrypt using our stored secretKey instead of// using the key bound to biometric authenticationreturndecryptWithStoredKey(encryptedData);}returnnull;}privateStringdecryptWithStoredKey(StringencryptedData){// Decrypt using the stored key, not the one from biometric authenticationtry{// This uses the class-level secretKey, not anything from the biometric resultCipherdecryptCipher=Cipher.getInstance("AES/GCM/NoPadding");decryptCipher.init(Cipher.DECRYPT_MODE,secretKey);returnnewString(decryptCipher.doFinal(Base64.decode(encryptedData,Base64.DEFAULT)));}catch(Exceptione){returnnull;}}}