Question

我必须实现Java密码空间填充。我试图写喜欢支持Perl代码的实现，其中支持Blowfish / CBC / space模式。我在Java密码列表中找不到相关的模式，仅支持PCK5Padding和NoPadding。 Java是否支持空格填充？有人可以帮助我吗？

Answer 1

Space填充会添加空格，因此加密时长度为8的倍数，解密后则修剪空格。在Java中，您可以使用NoPadding并自己管理间距。

例如，要在Perl中加密并在Java中解密：

Perl：

use Crypt::CBC;

$cipher = Crypt::CBC->new(
    -literal_key => 1,
    -key => pack("H*",
      "11223344556677889900112233445566778899001122334"
      . "455667788990011223344556677889900112233445566"
      . "77889900112233445566"),
    -cipher => 'Blowfish',
    -header => 'none',
    -padding => 'space',
    -iv => pack("H*", '1234567812345678')
);

$ciphertext = $cipher->encrypt_hex("Message");
print(join('',unpack('H*',$cipher->iv())));
print $ciphertext;

输出： 1234567812345678e70b9ab0a4262ba8

Java：

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

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

public class Main {
    public static void main(String[] args) throws Exception {
        Cipher cipher = Cipher.getInstance("Blowfish/CBC/NoPadding");
        SecretKeySpec key = new SecretKeySpec(Hex.decodeHex(
            "11223344556677889900112233445566778899001122334"
              + "455667788990011223344556677889900112233445566"
              + "77889900112233445566"),
            "Blowfish");
        byte[] iv = Hex.decodeHex("1234567812345678");

        cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));
        byte[] result = cipher.doFinal(Hex.decodeHex("e70b9ab0a4262ba8"));

        System.out.println(new String(result, Charsets.UTF_8).trim());
    }
}

输出： Message

如何实现Blowfish CBC算法空间填充

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