作者jimhu (胡小揚)
看板java
標題[問題] 關於3DES key與密文居相反的問題?
時間Fri Oct 5 14:40:41 2012
各位好
我要做的是一個使用3DES加解密的程式
範例是
DATA: 00 00 00 00 00 00 00 00
KEYA: 40 42 44 46 48 4A 7E 00
KEYB: 00 7E 60 62 64 66 68 6A
算出來為
8C 7F 46 D7 6C E0 12 66
可是我寫出來的程式演算法應該是沒有問題
但key必須倒著輸入才會算出正確的值
且正確的值也是倒過來的XD
以下是程式碼
import java.security.Key;
import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
public class BcTest {
static void test() throws Exception {
byte[] data = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00 };
byte[] key1 = new byte[] { 0x00, 0x7E, (byte) 0x4A, (byte) 0x48, (byte) 0x46, (byte) 0x44, (byte) 0x42,
(byte) 0x40 };
byte[] key2 = new byte[] { (byte) 0x6A, (byte) 0x68, (byte) 0x66, (byte) 0x64, (byte) 0x62, (byte) 0x60, 0x7E,
0x00 };
// 3DES ciphertext = EK3(DK2(EK1(plaintext)))
byte[] crypt = encrypt(decrypt(encrypt(data, key1), key2), key1);
// 3DES plaintext = DK1(EK2(DK3(ciphertext)))
byte[] plain = decrypt(encrypt(decrypt(crypt, key1), key2), key1);
System.out.println(" key1: " + ByteUtil.bytes2HexSpace(key1) + "\n key2: "
+ ByteUtil.bytes2HexSpace(key2));
System.out.println(" data: " + ByteUtil.bytes2HexSpace(data));
System.out.println("crypt: " + ByteUtil.bytes2HexSpace(crypt));
System.out.println("plain: " + ByteUtil.bytes2HexSpace(plain));
}
public static void main(String[] args) throws Exception {
test();
}
public static byte[] decrypt(byte[] crypt, byte[] key) throws Exception {
Key k = toKey(key);
Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, k);
return cipher.doFinal(crypt);
}
public static byte[] encrypt(byte[] data, byte[] key) throws Exception {
Key k = toKey(key);
Cipher cipher = Cipher.getInstance("DES/ECB/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, k);
return cipher.doFinal(data);
}
public static SecretKey toKey(byte[] key) throws Exception {
KeySpec dks = new DESKeySpec(key);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
return keyFactory.generateSecret(dks);
}
}
class ByteUtil {
private static final char HEX[] = "0123456789ABCFEF".toCharArray();
public static String bytes2HexSpace(byte bys[]) {
char chs[] = new char[(bys.length * 2 + bys.length) - 1];
int i = 0;
int offset = 0;
for (; i < bys.length; i++) {
if (i > 0)
chs[offset++] = ' ';
chs[offset++] = HEX[bys[i] >> 4 & 15];
chs[offset++] = HEX[bys[i] & 15];
}
return new String(chs);
}
}
我個人是覺得 LSB MSB的問題!?
麻煩各位解答了 感謝!
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 192.192.114.225
1F：推 pttnews:關於作業文不排版的問題 10/08 21:44
2F：→ pttnews:請原PO幫忙回答 10/08 21:46