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我正在尝试使用 PHP mcrypt 函数解密由 Java Triple DES 函数加密的密钥，但没有运气。在下面找到java代码

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


public class Encrypt3DES {

     private byte[] key;
     private byte[] initializationVector;

    public Encrypt3DES(){

    }

    public String encryptText(String plainText, String key) throws Exception{

         //----  Use specified 3DES key and IV from other source --------------
        byte[] plaintext = plainText.getBytes();
        byte[] myIV = key.getBytes();
        byte[] tdesKeyData = {(byte)0xA2, (byte)0x15, (byte)0x37, (byte)0x08, (byte)0xCA, (byte)0x62,
        (byte)0xC1, (byte)0xD2, (byte)0xF7, (byte)0xF1, (byte)0x93, (byte)0xDF,
        (byte)0xD2, (byte)0x15, (byte)0x4F, (byte)0x79, (byte)0x06, (byte)0x67,
        (byte)0x7A, (byte)0x82, (byte)0x94, (byte)0x16, (byte)0x32, (byte)0x95};

        Cipher c3des = Cipher.getInstance("DESede/CBC/PKCS5Padding");
        SecretKeySpec    myKey = new SecretKeySpec(tdesKeyData, "DESede");
        IvParameterSpec ivspec = new IvParameterSpec(myIV);
           c3des.init(Cipher.ENCRYPT_MODE, myKey, ivspec);
        byte[] cipherText = c3des.doFinal(plaintext);
        sun.misc.BASE64Encoder obj64=new sun.misc.BASE64Encoder();
        return obj64.encode(cipherText);

    }

    public String decryptText(String encryptText, String key) throws Exception{


        byte[] initializationVector = key.getBytes();
        byte[] tdesKeyData = {(byte)0xA2, (byte)0x15, (byte)0x37, (byte)0x08, (byte)0xCA, (byte)0x62,
        (byte)0xC1, (byte)0xD2, (byte)0xF7, (byte)0xF1, (byte)0x93, (byte)0xDF,
        (byte)0xD2, (byte)0x15, (byte)0x4F, (byte)0x79, (byte)0x06, (byte)0x67,
        (byte)0x7A, (byte)0x82, (byte)0x94, (byte)0x16, (byte)0x32, (byte)0x95};


          byte[] encData = new sun.misc.BASE64Decoder().decodeBuffer(encryptText);
          Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
          SecretKeySpec myKey = new SecretKeySpec(tdesKeyData, "DESede");
          IvParameterSpec ivspec = new IvParameterSpec(initializationVector);
          decipher.init(Cipher.DECRYPT_MODE, myKey, ivspec);
          byte[] plainText = decipher.doFinal(encData);
          return new String(plainText);

    }
}

我想写一个与上面decryptText Java函数等效的PHP函数。我发现难以生成由 Java 代码生成的用于加密的确切 IV 值，这是解密所必需的。

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2 回答 2

9

这是您的 Java 代码的 PHP 等效项（我已从参考的20-Sep-2006 07:56注释中复制了 PKCS#5-padding ）mcrypt

function encryptText($plainText, $key) {
    $keyData = "\xA2\x15\x37\x08\xCA\x62\xC1\xD2"
        . "\xF7\xF1\x93\xDF\xD2\x15\x4F\x79\x06"
        . "\x67\x7A\x82\x94\x16\x32\x95";

    $padded = pkcs5_pad($plainText,
        mcrypt_get_block_size("tripledes", "cbc"));

    $encText = mcrypt_encrypt("tripledes", $keyData, $padded, "cbc", $key);

    return base64_encode($encText);
}

function decryptText($encryptText, $key) {
    $keyData = "\xA2\x15\x37\x08\xCA\x62\xC1\xD2"
        . "\xF7\xF1\x93\xDF\xD2\x15\x4F\x79\x06"
        . "\x67\x7A\x82\x94\x16\x32\x95";

    $cipherText = base64_decode($encryptText);

    $res = mcrypt_decrypt("tripledes", $keyData, $cipherText, "cbc", $key);

    $resUnpadded = pkcs5_unpad($res);

    return $resUnpadded;
}


function pkcs5_pad ($text, $blocksize)
{
    $pad = $blocksize - (strlen($text) % $blocksize);
    return $text . str_repeat(chr($pad), $pad);
}

function pkcs5_unpad($text)
{
    $pad = ord($text{strlen($text)-1});
    if ($pad > strlen($text)) return false;
    if (strspn($text, chr($pad), strlen($text) - $pad) != $pad) return false;
    return substr($text, 0, -1 * $pad);
}

但是有一些问题你应该注意：

  • In your Java code you call String.getBytes() without indicating an encoding. This makes your code non portable if your clear text contains non ASCII-characters such as umlauts, because Java uses the system-default character set. If you can change that I certainly would do so. I recommend you to use utf-8 on both sides (Java and PHP).
  • You have hard coded the cipher-key and use the IV as "key". I'm by no means a crypto-expert but to me it just feels wrong and may open a huge security leak.
  • Create a random IV and just concatenate it at the start or at the end of your message. Since the size of the IV is AFAIK equal to the block-size of your cipher you just remove that much bytes from the start or end and have easily separated the IV from the message.
  • As for the key, it's best to use some kind of key derivation method to generate a key with the right size from a "human generated" password.

Of course, if you have to fulfil some given requirements you can't change your method.

于 2011-12-16T07:16:37.110 回答
0

The answer is almost good! Just reverse $keyData and $key in 

$encText = mcrypt_encrypt("tripledes", $keyData, $padded, "cbc", $key);

and

$res = mcrypt_decrypt("tripledes", $keyData, $cipherText, "cbc", $key);

otherwise you will always use the same 3DES key. And it's better to rename $keyData to $iv.

Anyway, thanks a lot for the Java sample and the Php-Java translation.

于 2013-10-08T13:35:25.057 回答