java/php DES/CBC/PKCS5Padding加密解密算法实现过程

先看java代码 

public static String encrypt(String message, String key) throws Exception {
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");

        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
        IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);

        return toHexString(cipher.doFinal(message.getBytes("UTF-8")));
    }

public static String decrypt(String message, String key) throws Exception {

        byte[] bytesrc = convertHexString(message);
        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes("UTF-8"));
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
        IvParameterSpec iv = new IvParameterSpec(key.getBytes("UTF-8"));

        cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);

        byte[] retByte = cipher.doFinal(bytesrc);
        return new String(retByte);
    }

public static byte[] convertHexString(String ss) {
        byte digest[] = new byte[ss.length() / 2];
        for (int i = 0; i < digest.length; i++) {
            String byteString = ss.substring(2 * i, 2 * i + 2);
            int byteValue = Integer.parseInt(byteString, 16);
            digest[i] = (byte) byteValue;
        }

        return digest;
    }
    public static String toHexString(byte b[]) {
        StringBuffer hexString = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            String plainText = Integer.toHexString(0xff & b[i]);
            if (plainText.length() < 2)
                plainText = "0" + plainText;
            hexString.append(plainText);
        }

        return hexString.toString();
    }

java写的已经很明显使用的是CBC/PKCS补码方式 

在看PHP 

function encrypt($str) {
        //加密，返回大写十六进制字符串
        $size = mcrypt_get_block_size (MCRYPT_DES, MCRYPT_MODE_[color=red]CBC[/color] );
        $str = $this->pkcs5Pad ( $str, $size );
        return strtoupper( bin2hex( mcrypt_cbc(MCRYPT_DES, $this->key, $str, MCRYPT_ENCRYPT, $this->iv ) ) );
    }

    function decrypt($str) {
        //解密
        $strBin = $this->hex2bin( strtolower( $str ) );
        $str = mcrypt_cbc( MCRYPT_DES, $this->key, $strBin, MCRYPT_DECRYPT, $this->iv );
        $str = $this->pkcs5Unpad( $str );



        return $str;
    }
function hex2bin($hexData) {
        $binData = "";
        for($i = 0; $i  < strlen ( $hexData ); $i += 2) {
            $binData .= chr ( hexdec ( substr ( $hexData, $i, 2 ) ) );
        }
        return $binData;
    }

    function pkcs5Pad($text, $blocksize) {
        $pad = $blocksize - (strlen ( $text ) % $blocksize);
        return $text . str_repeat ( chr ( $pad ), $pad );
    }

    function pkcs5Unpad($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 );
    }