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我继承了一些 C# 代码，其中包含函数 &decrypt 的 PHP 页面被编译/转换为独立的 Windows EXE。我想采用这个 PHP 代码并将功能放入 C# 中。

function &decrypt($enc_text, $password)
{
    $iv_len = 16;
    $enc_text = base64_decode($enc_text);
    $i = $iv_len;
    $n = strlen($enc_text);
    $plain_text = '';
    $iv = substr($password ^ substr($enc_text, 0, $iv_len), 0, 512);
    while ($i < $n)
    {
        $block = substr($enc_text, $i, 16);
        $plain_text .= $block ^ pack('H*', md5($iv));
        $iv = substr($block . $iv, 0, 512) ^ $password;
        $i += 16;
        }
    return $plain_text;
}

我发现了几个提到此代码的问题，但没有提供太多见解： 只想将代码解码为纯文本 并将“MD5解密”php函数转换为MySQL存储函数

有用的链接： PHP base64_decode C# 等价物

http://nuronconsulting.com/c-pack-h.aspx

除了倒数第二个和第三个字符外，我可以获得正确的结果。我认为我的 base64 解码仍然关闭。

编辑：更新到正在使用的最新代码。删除了中间编辑。

    private string decipher(string ienc_text, string ipassword)
    {
        int iv_len = 16;
        byte[] toEncryptArray = Convert.FromBase64String(ienc_text);
        string encryptedStringx = System.Text.Encoding.Default.GetString(toEncryptArray);
        string encryptedString = Encoding.GetEncoding(28591).GetString(toEncryptArray);
        string password = ipassword;
        int i = iv_len;
        int n = encryptedString.Length;
        string plain_text = "";
        string iv = phpXOR(ipassword, encryptedString.Substring(0, iv_len));

        while (i < n)
        {
            string block = encryptedString.Substring(i, iv_len);

            string md5 = getMD5(iv);

            byte[] testPack = PackH(md5);
            string testPackstring = Encoding.Default.GetString(testPack);

            string tmp = phpXOR(block, testPackstring);

            plain_text += tmp;

            string block_iv = block + iv;
            string tmp_iv = block_iv;

            if (block_iv.Length > 512)
            {
                tmp_iv = block_iv.Substring(0, 512);
            }

            iv = phpXOR(tmp_iv, password);
            i += 16;
        }

        return plain_text;
    }

    public static byte[] PackH(string hex)
    {
        if ((hex.Length % 2) == 1) hex += '0';
        byte[] bytes = new byte[hex.Length / 2];
        for (int i = 0; i < hex.Length; i += 2)
        {
            bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
        }
        return bytes;
    }

    string phpXOR(string text, string key)
    {
        byte[] result = new byte[key.Length];

        for (int c = 0; c < key.Length; c++)
            result[c] = (byte)(((byte)text[c]) ^ ((byte)key[c]));

        return Encoding.Default.GetString(result);
    }

    public static string getMD5(string iValue)
    {
        byte[] textBytes = System.Text.Encoding.Default.GetBytes(iValue);
        //byte[] textBytes = System.Text.Encoding.GetEncoding(28591).GetBytes(password);

        try
        {
            System.Security.Cryptography.MD5CryptoServiceProvider cryptHandler;
            cryptHandler = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte[] hash = cryptHandler.ComputeHash(textBytes);
            string ret = "";
            foreach (byte a in hash)
            {
                if (a < 16)
                    ret += "0" + a.ToString("x");
                else
                    ret += a.ToString("x");
            }
            return ret;
        }
        catch
        {
            throw;
        }
    }
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1 回答 1

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循环中的代码不完整（因此注释掉的代码），但是，我提出的问题得到了回答。编码、XOR 问题、php 包复制是通过问题中的有用链接完成的。

    private string decipher(string ienc_text, string ipassword)
    {
        int iv_len = 16;
        byte[] toEncryptArray = Convert.FromBase64String(ienc_text);
        string encryptedString = Encoding.GetEncoding("iso-8859-1").GetString(toEncryptArray);
        string password = ipassword;
        int i = iv_len;
        int n = encryptedString.Length;
        string plain_text = "";
        string iv = phpXOR(ipassword, encryptedString.Substring(0, iv_len));

        while (i < n)
        {
            string block = encryptedString.Substring(i, iv_len);

            string md5 = getMD5(iv);

            byte[] testPack = PackH(md5);
            string testPackstring = Encoding.GetEncoding("iso-8859-1").GetString(testPack);

            string tmp = phpXOR(block, testPackstring);

            plain_text += tmp;

            //string block_iv = block + iv;
            //string tmp_iv = block_iv;

            //if (block_iv.Length > 512)
            //{
            //    tmp_iv = block_iv.Substring(0, 512);
            //}

            //iv = phpXOR(tmp_iv, password);
            //i += 16;
        }

        return plain_text;
    }

    public static byte[] PackH(string hex)
    {
        if ((hex.Length % 2) == 1) hex += '0';
        byte[] bytes = new byte[hex.Length / 2];
        for (int i = 0; i < hex.Length; i += 2)
        {
            bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
        }
        return bytes;
    }

    string phpXOR(string text, string key)
    {
        byte[] result = new byte[key.Length];

        for (int c = 0; c < key.Length; c++)
            result[c] = (byte)(((byte)text[c]) ^ ((byte)key[c]));

        return Encoding.Default.GetString(result);
    }

    public static string getMD5(string iValue)
    {
        byte[] textBytes = System.Text.Encoding.Default.GetBytes(iValue);

        try
        {
            System.Security.Cryptography.MD5CryptoServiceProvider cryptHandler;
            cryptHandler = new System.Security.Cryptography.MD5CryptoServiceProvider();
            byte[] hash = cryptHandler.ComputeHash(textBytes);
            string ret = "";
            foreach (byte a in hash)
            {
                if (a < 16)
                    ret += "0" + a.ToString("x");
                else
                    ret += a.ToString("x");
            }
            return ret;
        }
        catch
        {
            throw;
        }
    }
于 2012-08-24T15:59:25.493 回答