Android上本地计数器的安全管理

在Android系统中，可以使用Android KeyStore API来安全地管理本地计数器。

示例代码：

// 获取KeyStore实例 KeyStore keyStore = KeyStore.getInstance(ANDROID_KEY_STORE); keyStore.load(null);

// 创建或获取放置计数器的密钥 KeyGenParameterSpec.Builder keyBuilder = new KeyGenParameterSpec.Builder(KEY_ALIAS, KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT) .setBlockModes(KeyProperties.BLOCK_MODE_GCM) .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE) .setKeySize(KEY_SIZE) .setUserAuthenticationRequired(true) .setUserAuthenticationValidityDurationSeconds(USER_AUTHENTICATION_VALIDITY_DURATION_SECONDS); KeyGenParameterSpec keySpec = keyBuilder.build();

KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, ANDROID_KEY_STORE); keyPairGenerator.initialize(keySpec);

if (!keyStore.containsAlias(KEY_ALIAS)) { keyPairGenerator.generateKeyPair(); }

// 对计数器进行加密 Cipher cipher = Cipher.getInstance(KeyProperties.KEY_ALGORITHM_AES + "/" + KeyProperties.BLOCK_MODE_GCM + "/" + KeyProperties.ENCRYPTION_PADDING_NONE); cipher.init(Cipher.ENCRYPT_MODE, keyStore.getKey(KEY_ALIAS, null));

byte[] encryptedCounter = cipher.doFinal(counter.toByteArray());

// 对计数器进行解密 cipher.init(Cipher.DECRYPT_MODE, keyStore.getCertificate(KEY_ALIAS).getPublicKey(), new GCMParameterSpec(GCM_TAG_LENGTH, counterTag)); byte[] decryptedCounter = cipher.doFinal(counterEncrypt);

BigInteger counter = new BigInteger(decryptedCounter); counter = counter.add(BigInteger.ONE);

// 将计数器进行加密并存储 cipher.init(Cipher.ENCRYPT_MODE, keyStore.getKey(KEY_ALIAS, null)); byte[] encryptedCounter = cipher.doFinal(counter.toByteArray()); persistentStorage.store(KEY_ALIAS, encryptedCounter);

// 从存储中获取并解密计数器 byte[] encryptedCounter = persistentStorage.load(KEY_ALIAS); cipher.init(Cipher.DECRYPT_MODE, keyStore.getCertificate(KEY_ALIAS).getPublicKey(), new GCMParameterSpec(GCM_TAG_LENGTH, counterTag)); byte[] decryptedCounter = cipher.doFinal(encryptedCounter);

// 转换回BigInteger类型的计数器 BigInteger counter = new BigInteger(decryptedCounter);