在尝试首次实施AES-GCM时,我们在生成AuthenticationTag,Encrypted cipher& amp; GCM mac检查最终失败。对于当前实施,tag[]
正在填充,但byte[] encrypted
仍为空。因此cipher.doFinal(data1, offset)
给出了mac check in GCM failed
'。它似乎是围绕字节数组大小的一些问题,有人可以分享在什么基础上确定输出缓冲区大小?这应该以块的形式完成吗?
任何指向AES-GCM实施的指针/链接都将受到高度赞赏。
以下是我们的实施:
public class GCMTest {
public static void main(String[] args) throws Exception {
//***********************************************************
//Key
byte[] key = MessageDigest.getInstance("MD5").digest("1234567890123456".getBytes("UTF-8"));//this is the random key
//Iv
SecureRandom srand = SecureRandom.getInstance("SHA1PRNG");
byte[] iv = new byte[256];
srand.nextBytes(iv);
//Input
byte[] data="inputPlainText".getBytes();
final GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(16 * Byte.SIZE, iv);
//***********************************************************
//Encryption
final Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding", new BouncyCastleProvider());
cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key, "AES"), gcmParameterSpec);
cipher.updateAAD("MyAAD".getBytes("UTF-8"));
//Encrypted output
final byte[] encrypted = new byte[cipher.getOutputSize(data.length)];
cipher.update(data, 0, data.length, encrypted, 0); //Not being updated for current data.
//Tag output
byte[] tag = new byte[cipher.getOutputSize(data.length)];
cipher.doFinal(tag, 0);
//***********************************************************
//Decryption
final SecretKeySpec keySpec = new SecretKeySpec(key, "AES");
cipher.init(Cipher.DECRYPT_MODE, keySpec, gcmParameterSpec);
cipher.updateAAD("MyAAD".getBytes("UTF-8"));
//What size should be assigned to outputBuffer?
final byte[] data1 = new byte[256];
int offset = cipher.update(encrypted, 0, encrypted.length, data1, 0);
cipher.update(tag, 0, tag.length, data1, offset);
cipher.doFinal(data1, offset);
boolean isValid = checkEquals(data, data1);
System.out.println("isValid :"+isValid);
}
private static boolean checkEquals(byte[] a, byte[] b)
{
int diff = a.length ^ b.length;
for(int i = 0; i < a.length && i < b.length; i++)
diff |= a[i] ^ b[i];
return diff == 0;
}
}
它提供以下例外:
Exception in thread "main" javax.crypto.AEADBadTagException: mac check in GCM failed
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
at org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher$AEADGenericBlockCipher.doFinal(Unknown Source)
at org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher.engineDoFinal(Unknown Source)
at javax.crypto.Cipher.doFinal(Cipher.java:2068)
at GCMTest.main(GCMTest.java:56)
提前致谢!!
答案 0 :(得分:7)
我遇到了同样的问题。对我来说,它与编码字符串有关。我最终做了:
然后解密字符串我做了:
以下是代码:
private String encrypt(String src) {
byte[] srcBytes = src.getBytes(StandardCharsets.US_ASCII);
cipher.init(Cipher.ENCRYPT_MODE, secretKey, secureRandom);
byte[] cipherText = cipher.doFinal(srcBytes);
byte[] encryptedBytes = new byte[12 + cipherText.length];
System.arraycopy(ivBytes, 0, encryptedBytes, 0, 12);
System.arraycopy(cipherText, 0, encryptedBytes, 12, cipherText.length);
return Base64.encodeToString(encryptedBytes, Base64.DEFAULT);
}
private String decrypt(String encryptedString) {
byte[] encryptedBytes = Base64.decode(encryptedString, Base64.DEFAULT);
cipher.init(Cipher.DECRYPT_MODE, secretKey, new GCMParameterSpec(128, encryptedBytes, 0, 12));
byte[] decryptedBytes = cipher.doFinal(encryptedBytes, 12, encryptedBytes.length-12);
return Base64.encodeToString(decryptedBytes, Base64.DEFAULT);
}
我没有包含如何初始化它们的任何变量都可以从java文档中推断出来。我试图在Android中这样做,所以我不确定它有多么不同。我发现这篇文章非常有帮助:Java AES/GCM/NoPadding - What is cipher.getIV() giving me?
答案 1 :(得分:0)
您应该更新部分代码
错误区号:
void Main()
{
int[] operationIds = { 1000, 1001 };
var result = ObjectContext.ExecuteStoreQuery<EncyptedPatientInfoDataContract>(
$@"SELECT OperationId, Name, OfficialId, IsPatientEncrypted FROM Patient WHERE OperationId IN ({string.Join(",", operationIds)})");
result.Dump();
}
更新新代码:
//What size should be assigned to outputBuffer?
final byte[] data1 = new byte[256];
int offset = cipher.update(encrypted, 0, encrypted.length, data1, 0);
cipher.update(tag, 0, tag.length, data1, offset);
cipher.doFinal(data1, offset);