以下是用于生成加密和解密数据密钥的管理代码。相同的密钥用于加密和解密
public class AdminKeyGenerator {
private static final String ALGORITHM = "AES";
public static SecretKey generateKey() throws NoSuchAlgorithmException,
NoSuchPaddingException {
KeyGenerator genarator = KeyGenerator.getInstance(ALGORITHM);
SecretKey secretkey = genarator.generateKey();
return secretkey;
}
public static void saveKey(SecretKey key) {
File keyFile = new File("/home/thamiz/workspace/keyFile.txt");
try{
keyFile.createNewFile();
FileWriter keyWriter = new FileWriter(keyFile);
BufferedWriter buffKey = new BufferedWriter(keyWriter);
char[] hex = encodeHex( key.getEncoded() );
buffKey.write(hex);
buffKey.flush();
buffKey.close();
}catch(FileNotFoundException e){
System.out.println("Decryption fails");
} catch (IOException e) {
System.out.println("Decryption fails");
}
}
public static SecretKey loadKey() throws DecoderException{
File keyFile = new File("/home/thamiz/workspace/keyFile.txt");
String data = null;
byte[] encoded = null;
try{
FileReader keyReader = new FileReader( keyFile );
BufferedReader buffKeyRead = new BufferedReader(keyReader);
data = buffKeyRead.readLine();
encoded = decodeHex(data.toCharArray());
buffKeyRead.close();
}catch( IOException e ){
System.out.println("Decryption fails");
}
return new SecretKeySpec(encoded, ALGORITHM);
}
public static void main(String[] args) throws NoSuchAlgorithmException,
NoSuchPaddingException {
SecretKey secretkey = AdminKeyGenerator.generateKey();
AdminKeyGenerator.saveKey(secretkey);
}
Following is the client side code. client used the admin key and encrypt his card details.
private static String debitcardType;
private static int debitCardNumber;
private static int debitcardCVV;
private static Date debitcardExpiryDate;
public static void storeCardDetails() throws ParseException {
Scanner in = new Scanner(System.in);
boolean anotherCardDetail = false;
SimpleDateFormat expiry = new SimpleDateFormat("dd-MM-yyyy");
do {
System.out.println("Enter your debit card type:");
debitcardType = in.next();
System.out.println("Enter your debit card number:");
debitCardNumber = in.nextInt();
System.out.println("Enter your debit card cvv number:");
debitcardCVV = in.nextInt();
System.out.println("Enter your debit card expiry date in the format of dd-MM-yyyy:");
String date = in.next();
debitcardExpiryDate = expiry.parse(date);
System.out.println("Do you want to enter another card detail");
System.out.println("Enter 1 for another card details and 0 for exit ");
int option = in.nextInt();
if (!(option == 1) && (option == 0)) {
anotherCardDetail = true;
System.out.println("Exit from entering card details");
}
} while (!anotherCardDetail);
}
private static String encryptCardDetails(int cardNumber, int cardCVV,Date expiryDate, SecretKey key)
{
Cipher cipherencrypt = Cipher.getInstance("AES");
byte[] plainCardNumber = String.valueOf(cardNumber).getBytes();
byte[] plainCardCVV = String.valueOf(cardCVV).getBytes();
byte[] plainExpiryDate = expiryDate.toString().getBytes();
cipherencrypt.init( cipherencrypt.ENCRYPT_MODE, key);
byte[] encryptedCardNumber = cipherencrypt.doFinal(plainCardNumber);
byte[] encryptedCardCVV = cipherencrypt.doFinal(plainCardCVV);
byte[] encryptedExpiryDate = cipherencrypt.doFinal(plainExpiryDate);
String encryptedCard = Base64.encodeBase64String(encryptedCardNumber)
+ Base64.encodeBase64String(encryptedCardCVV)
+ Base64.encodeBase64String(encryptedExpiryDate);
return encryptedCard;
}
public static String decryptCardDetails( File file, SecretKey key ) {
byte[] finalString1 = null;
byte[] finalString2 = null;
byte[] finalString3 = null;
String final1 = null,final2 = null, final3 = null;
Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");
try{
FileReader decryptFile = new FileReader(file);
BufferedReader buff = new BufferedReader(decryptFile);
String decryptcontent = buff.readLine();
Scanner scan = new Scanner(decryptcontent).useDelimiter(",");
String cardType = scan.next();
System.out.println(cardType);
String decryptString = scan.next();
System.out.println(decryptString);
byte[] decrypt1 = Base64.decodeBase64(decryptString);
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] decryptedText = cipher.doFinal(decrypt1);
final3 = new String(decryptedText, "UTF-8");
decryptedCardNumber.toString()+decryptedCardCVV.toString()+decryptedExpiryDate.toString();
}catch( IOException e ) {
System.out.println("Decryption fails");
}
return final3;
}
public static void main(String[] args) {
File cardDetailsFile = new File("/home/thamiz/workspace/cardFile.txt");
try {
cardDetailsFile.createNewFile();
FileWriter fileOut = new FileWriter(cardDetailsFile);
BufferedWriter buffer = new BufferedWriter(fileOut);
ClientCardDetails.storeCardDetails();
AdminKeyGenerator.generateKey();
String card = ClientCardDetails.encryptCardDetails(debitCardNumber, debitcardCVV,
debitcardExpiryDate, AdminKeyGenerator.generateKey());
buffer.write(debitcardType);
buffer.write(",");
buffer.write(card);
buffer.newLine();
buffer.flush();
SecretKey key = AdminKeyGenerator.loadKey();
String card1 = ClientCardDetails.decryptCardDetails(cardDetailsFile, key );
System.out.println("Decryption sucessful");
System.out.println(card1);
} catch (ParseException e) {
System.out.println("Enter incorrect card details");
} catch (IOException e) {
System.out.println("Encryption fails");
}
}
以上程序提供以下输出
主 SNIakr8Iguta7i0nqB + QPG == VjmLfQj / YLUJUQnhJCYrgg == 7U1XrYRf8vqw + 5nUK8IgFFH8KqLsEKBXlIi9AnxVwzo = 解密成功 jiPHL
答案 0 :(得分：1)
在“客户端代码”中，您在AdminKeyGenerator.generateKey()的{{1}}内拨打AdminKeyGenerator两次，每次通话都会返回一个新的唯一键。
具体地，
main()使用新生成的密钥进行加密。然后钥匙就被丢弃了。结果永远不会再被解密。
确保只生成一个密钥，然后保存密钥，并（加载和）使用一个密钥进行每次加密和解密。
此外，您在一个地方String card = ClientCardDetails.encryptCardDetails(
debitCardNumber,
debitcardCVV,
debitcardExpiryDate,
AdminKeyGenerator.generateKey()
);
，在另一个地方Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");。使用完全相同的密码配置进行加密和解密！