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import java.io.*;
import java.security.MessageDigest;
import java.security.Security;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
public class NewKey{
public static void main(String[] args) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
String username = "[email protected]";
String userdata = "depression"+" "+"headache";
// Get the Key
byte[] key = (username).getBytes();
MessageDigest sha = MessageDigest.getInstance("SHA-256");
key = sha.digest(key);
key = Arrays.copyOf(key, 16);
SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
System.out.println("key used is "+username);
System.out.println("encrypted key used is "+key);
Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding", "BC");
final byte[] IV = {-85, -67, -5, 88, 28, 49, 49, 85,114, 83, -40, 119, -65, 91, 76, 108};// Hard coded for now
final IvParameterSpec ivSpec = new IvParameterSpec(IV);
System.out.println("Derived AES key is: " +secretKeySpec.toString().getBytes().length);
cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec,ivSpec);
byte[] encrypted = cipher.doFinal((userdata).getBytes());
System.out.println("encrypted userdata: " + encrypted);
cipher.init(Cipher.DECRYPT_MODE, secretKeySpec,ivSpec);
byte[] original = cipher.doFinal(encrypted);
String originalString = new String(original);
System.out.println("Original userdata: " + originalString);
}
}
초기화 벡터 (IV)에 몇 가지 값을 사용했으며 AES CTR 모드를 사용하는 올바른 방법을 알고 싶습니다.패딩없이 CTR 모드를 사용하는 올바른 방법은 무엇입니까?
key = Arrays.copyOf(key, 16);
위 문장의 목적은 무엇입니까? 은 프로그램을 강화하기위한 몇 가지 변화를 제안합니다.