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DES加密中不同密钥加密出来的内容一样，解密也一样，为什么？

发布于 2022-01-03 13:33:56 字数 237 浏览 528 评论 15

明文为：QKCXRHFAZMGVUHQN

密钥：PPPPPPPPPPPPPPPP 或者 QQQQQQQQQQQQQQQQ

采用DESede/ECB/NoPadding 进行加密

加密后密转换为16进制密文为：AAEAAF2DABDE20366516B2734EFBB967

该过程中可以把P和Q随意替换，密文不变。

请问有知道这是为什么的吗？

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如日中天 2022-01-07 19:54:51

@LiYong_Luke 是对的

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冬天旳寂寞 2022-01-07 19:54:50

@LiYong_Luke 是对的

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秋意浓 2022-01-07 19:54:33

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@120011676 : 96

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风苍溪 2022-01-07 19:54:24

DES的密钥是64位，它分成的8组，每一组的最后一位是校验位，因此有效密钥是56位，因此对于java，只能8个P。太多或太少都会是Wrong key size

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清欢 2022-01-07 19:52:15

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我看错了，你是DESede, 那密码应该是24个P。因为它需要的是168位有效密钥

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南冥有猫 2022-01-07 19:52:07

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杠上了，8P也不对，楼主也不贴他代码

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等你爱我 2022-01-07 19:50:17

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@120011676 : 24P,对了

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本王不退位尔等都是臣 2022-01-07 19:41:39

你们讨论那么激烈，我试了下，楼主JavaScript吧？java不能用这个key。

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

public class DESedeTest {
    public static void main(String[] args) throws Exception {
        String key = "PPPPPPPPPPPPPPPP";
        String content = "QKCXRHFAZMGVUHQN";
        System.out.println(Hex.encodeHexString(ec(key.getBytes(), content.getBytes())));
        String m = ec(key, content);
        System.out.println(ec(key, content));
        System.out.println(dc(key, m));
        System.out.println(dc("QQQQQQQQQQQQQQQQ", m));

    }

    public static String ec(String key, String content) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
        String Algorithm = "DESede/ECB/NoPadding";
        SecretKey secretKey = new SecretKeySpec(key.getBytes(), "DESede");
        Cipher c1 = Cipher.getInstance(Algorithm);
        c1.init(Cipher.ENCRYPT_MODE, secretKey);
        return Hex.encodeHexString(c1.doFinal(content.getBytes()));
    }

    public static String dc(String key, String content) throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException, DecoderException {
        String Algorithm = "DESede/ECB/NoPadding";
        SecretKey secretKey = new SecretKeySpec(key.getBytes(), "DESede");
        Cipher c1 = Cipher.getInstance(Algorithm);
        c1.init(Cipher.DECRYPT_MODE, secretKey);
        return new String(c1.doFinal(Hex.decodeHex(content.toCharArray())));
    }

    public static byte[] ec(byte[] key, byte[] data)
            throws Exception {
        SecretKey deskey = new SecretKeySpec(key, "desede");
        Cipher cipher = Cipher.getInstance("DESede/ECB/NOPADDING");
        cipher.init(Cipher.ENCRYPT_MODE, deskey);
        return cipher.doFinal(data);
    }

    public static byte[] de(byte[] key, byte[] data)
            throws Exception {
        SecretKey deskey = new SecretKeySpec(key, "DESede");
        Cipher cipher = Cipher.getInstance("DESede/ECB/NOPADDING");
        cipher.init(Cipher.DECRYPT_MODE, deskey);
        return cipher.doFinal(data);
    }

}

Exception in thread "main" java.security.InvalidKeyException: Wrong key size
   at java.base/com.sun.crypto.provider.DESedeCrypt.init(DESedeCrypt.java:69)
   at java.base/com.sun.crypto.provider.ElectronicCodeBook.init(ElectronicCodeBook.java:95)
   at java.base/com.sun.crypto.provider.CipherCore.init(CipherCore.java:591)
   at java.base/com.sun.crypto.provider.CipherCore.init(CipherCore.java:467)
   at java.base/com.sun.crypto.provider.DESedeCipher.engineInit(DESedeCipher.java:166)
   at java.base/javax.crypto.Cipher.implInit(Cipher.java:870)
   at java.base/javax.crypto.Cipher.chooseProvider(Cipher.java:932)
   at java.base/javax.crypto.Cipher.init(Cipher.java:1302)
   at java.base/javax.crypto.Cipher.init(Cipher.java:1239)
   at DESedeTest.ec(DESedeTest.java:41)
   at DESedeTest.main(DESedeTest.java:13)

Process finished with exit code 1

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