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Decrypting AES-encrypted data involves using the AES key, initialization vector (IV), nonce, and authentication tag. Here's a basic example in Java using the Java Cryptography Architecture (JCA) library:
```java
import javax.crypto.*;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
public class AESDecryptionExample {
public static void main(String[] args) throws Exception {
// Replace these values with your actual AES key, IV, nonce, and tag
byte[] aesKey = hexStringToByteArray("yourAESKeyInHex");
byte[] iv = hexStringToByteArray("yourIVInHex");
byte[] nonce = hexStringToByteArray("yourNonceInHex");
byte[] tag = hexStringToByteArray("yourTagInHex");
// Replace this ciphertext with your actual encrypted data
byte[] ciphertext = hexStringToByteArray("yourEncryptedDataInHex");
// Decrypt the data
byte[] decryptedData = decryptAESGCM(ciphertext, aesKey, iv, nonce, tag);
// Print the decrypted data
System.out.println("Decrypted Data: " + new String(decryptedData, "UTF-8"));
}
private static byte[] decryptAESGCM(byte[] ciphertext, byte[] aesKey, byte[] iv, byte[] nonce, byte[] tag)
throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidAlgorithmParameterException,
InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
// Create the GCMParameterSpec using IV, nonce, and tag
GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(tag.length * 8, nonce);
// Initialize the cipher with the key, mode, and parameters
SecretKeySpec keySpec = new SecretKeySpec(aesKey, "AES");
cipher.init(Cipher.DECRYPT_MODE, keySpec, gcmParameterSpec);
// Decrypt the ciphertext
return cipher.doFinal(ciphertext);
}
private static byte[] hexStringToByteArray(String hex) {
int len = hex.length();
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4)
+ Character.digit(hex.charAt(i + 1), 16));
}
return data;
}
}
```
Make sure to replace "yourAESKeyInHex," "yourIVInHex," "yourNonceInHex," "yourTagInHex," and "yourEncryptedDataInHex" with your actual AES key, IV, nonce, tag, and encrypted data in hexadecimal form.
Note: This example assumes you are using AES in GCM (Galois/Counter Mode) mode for authenticated encryption. Adjust the algorithm and mode accordingly based on your encryption setup. Also, handle exceptions and errors appropriately in a production environment.Editor is loading...
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