android - KeyStoreException : Signature/MAC verification failed when trying to decrypt

我正在尝试创建一个简单的Kotlin对象，该对象通过在保存之前对内容进行加密来包装对应用程序的共享首选项的访问。

加密似乎可以正常工作，但是当我尝试解密时，我收到一个javax.crypto.AEADBadTagException，它从“android.security.KeyStoreException:签名/MAC验证失败”触发。

我尝试调试以查看潜在问题是什么，但找不到任何东西。没有任何搜索提供给我任何线索，我似乎遵循了这封信的一些指南，但没有成功。

private val context: Context?
    get() = this.application?.applicationContext
private var application: Application? = null

private val transformation = "AES/GCM/NoPadding"
private val androidKeyStore = "AndroidKeyStore"
private val ivPrefix = "_iv"
private val keyStore by lazy { this.createKeyStore() }

private fun createKeyStore(): KeyStore {
    val keyStore = KeyStore.getInstance(this.androidKeyStore)
    keyStore.load(null)
    return keyStore
}

private fun createSecretKey(alias: String): SecretKey {
    val keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, this.androidKeyStore)

    keyGenerator.init(
        KeyGenParameterSpec.Builder(alias, KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT)
            .setBlockModes(KeyProperties.BLOCK_MODE_GCM)
            .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
            .build()
    )

    return keyGenerator.generateKey()
}

private fun getSecretKey(alias: String): SecretKey {
    return if (this.keyStore.containsAlias(alias)) {
        (this.keyStore.getEntry(alias, null) as KeyStore.SecretKeyEntry).secretKey
    } else {
        this.createSecretKey(alias)
    }
}

private fun removeSecretKey(alias: String) {
    this.keyStore.deleteEntry(alias)
}

private fun encryptText(alias: String, textToEncrypt: String): String {
    val cipher = Cipher.getInstance(this.transformation)
    cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(alias))

    val ivString = Base64.encodeToString(cipher.iv, Base64.DEFAULT)
    this.storeInSharedPrefs(alias + this.ivPrefix, ivString)

    val byteArray = cipher.doFinal(textToEncrypt.toByteArray(charset("UTF-8")))
    return String(byteArray)
}

private fun decryptText(alias: String, textToDecrypt: String): String? {
    val ivString = this.retrieveFromSharedPrefs(alias + this.ivPrefix) ?: return null

    val iv = Base64.decode(ivString, Base64.DEFAULT)
    val spec = GCMParameterSpec(iv.count() * 8, iv)
    val cipher = Cipher.getInstance(this.transformation)
    cipher.init(Cipher.DECRYPT_MODE, getSecretKey(alias), spec)

    try {
        val byteArray = cipher.doFinal(textToDecrypt.toByteArray(charset("UTF-8")))
        return String(byteArray)
    } catch (e: Exception) {
        e.printStackTrace()
        return null
    }
}

private fun storeInSharedPrefs(key: String, value: String) {
    this.context?.let {
        PreferenceManager.getDefaultSharedPreferences(it).edit()?.putString(key, value)?.apply()
    }
}

private fun retrieveFromSharedPrefs(key: String): String? {
    val validContext = this.context ?: return null
    return PreferenceManager.getDefaultSharedPreferences(validContext).getString(key, null)
}

谁能指出我正确的方向？

最佳答案

当您将身份验证标签的长度从iv.count()更改为128时，它将起作用。

关于android - KeyStoreException : Signature/MAC verification failed when trying to decrypt，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/55665337/