Related to this question: Cannot decrypt AES-256 GCM with Java
The Java decrypt issue seems to only be fixed if the encrypted message is short, i.e. two words or so. I've tried with the words, "hello" and "short string", and both of these words were decrypted fine. When I tried something like,
Alphanumeric string test1 with more numbers such as 5, 4, 3, 2, 1
AEADBadTagException came up again.
EDIT:
This issue is directly related to how long the encrypted message is. Two words is a bit of an exaggeration, but as long as the encrypted message is about as long as this or longer then Java will run into the exception.
Encrypted message sample:
d+nyOuSfH3wup+5KHJRQyVwVHE0nn7dOfLQsSxb2LsR1LuogHxmVobHoQSTbdyqupd/UvwGfbhkUQz+8CjIBSd7FoEVpgpYv9dAQ3GGUr3AtA+rJJrFHo/EM443sQlSOG4cIBQ7trF7udmrIhtiZ9wMchaBEJFmDBL5Jwl8ZMM0ath8VNWqfyyhghPW8U2NiORAy5mw6v07o7v3UT2 lBzJThBsM=
Decrypted with node:
this is a longer string to make the encrypted message longer than before
EDIT 2:
Java code:
package decryption;
import java.io.UnsupportedEncodingException;
import java.util.Arrays;
import java.util.Base64;
import javax.crypto.Cipher;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
public class DecryptAES256 {
private static String salt;
private static byte[] iv;
private static byte[] encryptedMessageAndTag;
private static byte[] key;
public static void main(String[] args) {
String key = "123456789aabbccddeefffffffffffff";
String sourceText = "zMX8Xp8lCLGP3FsF7dy1uEODFG0+lhpoWR+xZPpNAXm2D39+CJUK5Kk0z4NbDfb/WbP8lHVWcTOuXf8hRA1AmtEV2G5kP3SH3mrGbyf4QthR4aOTqEQQAvt1T8LlIkBlgx32gehP/nwwm3DYyJV+NnN21Ac17L4=";
System.out.println(decrypt(key, sourceText));
}
public static String decrypt(String masterkey, String encryptedText) {
// decode encryptedText
encryptedText = new String(Base64.getDecoder().decode(encryptedText.getBytes()));
// extract the different parts
byte[] parts = encryptedText.getBytes();
salt = new String(Arrays.copyOfRange(parts, 0, 64)); // not using for testing purposes
iv = Arrays.copyOfRange(parts, 64, 76);
encryptedMessageAndTag = Arrays.copyOfRange(parts, 76, parts.length);
try {
key = masterkey.getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
// not going to reach here
}
// call helper method to decrypt
byte[] decipheredText = decodeAES_256_CBC();
return new String(decipheredText);
}
private static byte[] decodeAES_256_CBC() {
try {
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
GCMParameterSpec params = new GCMParameterSpec(128, iv, 0, iv.length);
cipher.init(Cipher.DECRYPT_MODE, skeySpec, params);
return cipher.doFinal(encryptedMessageAndTag);
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException("Failed to decrypt");
}
}
}
EDIT 3:
Cleaned up Java code for readability
来源:https://stackoverflow.com/questions/46307621/cannot-decrypt-long-aes-256-gcm-message-with-java