[英]Error decrypting message encrypted using AES/GCM/NoPadding in Android
我目前正在使用AES / GCM / NoPadding執行加密操作。
我的加密代碼:
fun encrypt(plainText: ByteArray, key: Key): ByteArray? {
var resultText: ByteArray? = null
try {
val cipher = Cipher.getInstance(ALGORITHM)
cipher.init(Cipher.ENCRYPT_MODE, key)
val cipherText = cipher.doFinal(plainText)
resultText = ByteBuffer.allocate(1 + cipher.iv.size + cipherText.size)
.put(cipher.iv.size.toByte())
.put(cipher.iv)
.put(cipherText)
.array()
} catch (e : Exception) {
Logger.e(TAG, "Error encrypting plain text", e)
}
return resultText
}
我的解密代碼:
fun decrypt(cipherTextWithHeaders: ByteArray, key: Key): ByteArray? {
var plainText: ByteArray? = null
try {
val cipher = Cipher.getInstance(ALGORITHM)
val ivSize = cipherTextWithHeaders[0].toInt()
val iv = ByteArray(ivSize)
System.arraycopy(cipherTextWithHeaders, 1, iv, 0, ivSize)
cipher.init(Cipher.DECRYPT_MODE, key, GCMParameterSpec(ivSize * 8, iv))
val headerLen = 1 + ivSize
val cipherText = ByteArray(cipherTextWithHeaders.size - headerLen)
System.arraycopy(cipherTextWithHeaders, headerLen, cipherText, 0, cipherTextWithHeaders.size - headerLen)
plainText = cipher.doFinal(cipherText)
} catch (e : Exception) {
Logger.e(TAG, "Error decrypting cipher text", e)
}
return plainText
}
我在上面的解密方法中執行doFinal時遇到此異常:
javax.crypto.IllegalBlockSizeException
at android.security.keystore.AndroidKeyStoreCipherSpiBase.engineDoFinal(AndroidKeyStoreCipherSpiBase.java:519)
at javax.crypto.Cipher.doFinal(Cipher.java:1736)
我在加密期間嘗試了以下選項:
val temp = ByteArray(12)
SecureRandom().nextBytes(temp)
cipher.init(Cipher.ENCRYPT_MODE, key, GCMParameterSpec(96, temp))
但這會引發以下錯誤:
java.security.InvalidAlgorithmParameterException: Caller-provided IV not permitted
at android.security.keystore.KeyStoreCryptoOperationUtils.getExceptionForCipherInit(KeyStoreCryptoOperationUtils.java:85)
at android.security.keystore.AndroidKeyStoreCipherSpiBase.ensureKeystoreOperationInitialized(AndroidKeyStoreCipherSpiBase.java:265)
at android.security.keystore.AndroidKeyStoreCipherSpiBase.engineInit(AndroidKeyStoreCipherSpiBase.java:148)
at javax.crypto.Cipher.tryTransformWithProvider(Cipher.java:2659)
at javax.crypto.Cipher.tryCombinations(Cipher.java:2570)
at javax.crypto.Cipher$SpiAndProviderUpdater.updateAndGetSpiAndProvider(Cipher.java:2475)
at javax.crypto.Cipher.chooseProvider(Cipher.java:566)
at javax.crypto.Cipher.init(Cipher.java:973)
at javax.crypto.Cipher.init(Cipher.java:908)
GCM身份驗證標簽的長度與IV長度無關。 AES-GCM的標准實際上是12
字節IV和128
位GCM標簽,請參閱RFC 5288,第3節 。
例:
String input = "abcdef";
byte[] key = new byte[16];
(new SecureRandom()).nextBytes(key);
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "AES"));
byte[] ciphertext = cipher.doFinal(input.getBytes());
byte[] iv = cipher.getIV();
GCMParameterSpec gcmspec = cipher.getParameters().getParameterSpec(GCMParameterSpec.class);
System.out.println("ciphertext: " + ciphertext.length + ", IV: " + iv.length + ", tLen: " + gcmspec.getTLen());
cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key, "AES"), new GCMParameterSpec(128, iv));
byte[] plaintext = cipher.doFinal(ciphertext);
System.out.println("plaintext : " + new String(plaintext));
打印:
ciphertext: 22, IV: 12, tLen: 128
plaintext : abcdef
嘗試將GCMParameterSpec(ivSize * 8, iv)
更改為GCMParameterSpec(128, iv)
。
盡管問題也可能出在外面,即密文可能編碼不正確或在某處被切斷。 檢查cipherText.length
。
java.security.InvalidAlgorithmParameterException: Caller-provided IV not permitted
這是Android加密實施的局限性; 它希望在加密期間自行生成IV。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.