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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.
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