笔记：des加解密，php和.net版的实现

php5.x版本，要添加php扩展php_mcrypt。

class STD3Des
{
    private $key = "";
    private $iv = "";

    /**
    * 构造，传递二个已经进行base64_encode的KEY与IV
    *
    * @param string $key
    * @param string $iv
    */
    function __construct ($key, $iv)
    {
        if (empty($key) || empty($iv)) {
            echo 'key and iv is not valid';
            exit();
        }
        $this->key = $key;
        $this->iv = $iv;
    }

    /**
    *加密
    * @param <type> $value
    * @return <type>
    */
    public function encrypt ($value)
    {
        $td = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_CBC, '');
        $iv = base64_decode($this->iv);
        $value = $this->PaddingPKCS7($value);
        $key = base64_decode($this->key);
        mcrypt_generic_init($td, $key, $iv);
        $ret = base64_encode(mcrypt_generic($td, $value));
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        return $ret;
    }

    /**
    *解密
    * @param <type> $value
    * @return <type>
    */
    public function decrypt ($value)
    {
        $td = mcrypt_module_open(MCRYPT_3DES, '', MCRYPT_MODE_CBC, '');
        $iv = base64_decode($this->iv);
        $key = base64_decode($this->key);
        mcrypt_generic_init($td, $key, $iv);
        $ret = trim(mdecrypt_generic($td, base64_decode($value)));
        $ret = $this->UnPaddingPKCS7($ret);
        mcrypt_generic_deinit($td);
        mcrypt_module_close($td);
        return $ret;
    }

    private function PaddingPKCS7 ($data)
    {
        $block_size = mcrypt_get_block_size('tripledes', 'cbc');
        $padding_char = $block_size - (strlen($data) % $block_size);
        $data .= str_repeat(chr($padding_char), $padding_char);
        return $data;
    }

    private function UnPaddingPKCS7($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);
    }
}


//使用
include('STD3Des.class.php');
$key='abcdefgh';
$iv='abcdefgh';
$msg='test string';
$des=new STD3Des(base64_encode($key),base64_encode($iv));
$rs1=$des->encrypt($msg);
echo $rs1.'<br />';
$rs2=$des->decrypt($rs1);
echo $rs2;

 

.net版本

sealed public class CryptoHelper
{
    /// <summary>
    /// Encrypts the specified input.
    /// </summary>
    /// <param name="input">The input.</param>
    /// <param name="key">key</param>
    /// <param name="iv">iv</param>
    /// <returns></returns>
    public static string EncryptDes(string input, byte[] key, byte[] iv)
    {
        if (input == null || input.Length == 0)
            return String.Empty;

        DESCryptoServiceProvider des = new DESCryptoServiceProvider();
        MemoryStream ms = null;
        CryptoStream encStream = null;
        StreamWriter sw = null;
        string result = String.Empty;

        try
        {
            ms = new MemoryStream();

            // Create a CryptoStream using the memory stream and the 
            // CSP DES key.  
            //des.Mode = CipherMode.CBC;
            //des.Padding = PaddingMode.PKCS7;  
            encStream = new CryptoStream(ms, des.CreateEncryptor(key, iv), CryptoStreamMode.Write);

            // Create a StreamWriter to write a string
            // to the stream.
            sw = new StreamWriter(encStream);

            // Write the plaintext to the stream.
            sw.Write(input);

            sw.Flush();
            encStream.FlushFinalBlock();
            ms.Flush();


            result = Convert.ToBase64String(ms.GetBuffer(), 0, Convert.ToInt32(ms.Length, CultureInfo.InvariantCulture));
        }
        finally
        {
            //close objects
            if (sw != null)
                sw.Close();
            if (encStream != null)
                encStream.Close();
            if (ms != null)
                ms.Close();
        }

        // Return the encrypted string
        return result;
    }
    /// <summary>
    /// Decrypts the specified input.
    /// </summary>
    /// <param name="input">the input.</param>
    /// <param name="key">key</param>
    /// <param name="iv">iv</param>
    /// <returns></returns>
    public static string DecryptDes(string input, byte[] key, byte[] iv)
    {
        byte[] buffer;
        try { buffer = Convert.FromBase64String(input); }
        catch (System.ArgumentNullException) { return String.Empty; }
        // length is zero, or not an even multiple of four (plus a few other cases)
        catch (System.FormatException) { return String.Empty; }

        DESCryptoServiceProvider des = new DESCryptoServiceProvider();
        MemoryStream ms = null;
        CryptoStream encStream = null;
        StreamReader sr = null;
        string result = String.Empty;

        try
        {
            ms = new MemoryStream(buffer);

            // Create a CryptoStream using the memory stream and the 
            // CSP DES key. 
            encStream = new CryptoStream(ms, des.CreateDecryptor(key, iv), CryptoStreamMode.Read);

            // Create a StreamReader for reading the stream.
            sr = new StreamReader(encStream);

            // Read the stream as a string.
            result = sr.ReadToEnd();
        }
        finally
        {
            //close objects
            if (sr != null)
                sr.Close();
            if (encStream != null)
                encStream.Close();
            if (ms != null)
                ms.Close();
        }

        return result;
    }
}


//调用

string key = "abcdefgh";
string iv = "abcdefgh";
string msg="test string";
string rs1 = CryptoHelper.EncryptDes(msg, System.Text.Encoding.ASCII.GetBytes(key), System.Text.Encoding.ASCII.GetBytes(iv));
string rs2 = CryptoHelper.DecryptDes(rs1, System.Text.Encoding.ASCII.GetBytes(key), System.Text.Encoding.ASCII.GetBytes(iv));