Question

我的应用和服务器之间存在通信问题。我正在使用RNCryptor来加密消息，然后我将其编码并传输到请求中的服务器。这在DATA头中完成，在http体内作为后期数据完成。我想我在转换和转换方面犯了一个错误。通过POST传输base64编码的消息。

如果我通过标题收到加密邮件，它每次都会完全解密。但是，如果我通过POST数据获取消息，我会得到不同的结果。大多数情况下，它失败了，否则它会部分解密（前几个字母），大约20个左右成功的解密。

objective-c代码是：

- (NSString *)sendEncryptedTestMessage:(NSString *)address{
    NSString* messageContent    = @"Hello my name is Bob.";
    NSError * error             = nil;
    NSString* responseString2   = nil;

    NSData*   postData = [RNEncryptor encryptData:[messageContent dataUsingEncoding:NSUTF8StringEncoding]
                                    withSettings:kRNCryptorAES256Settings
                                        password:@"123456"
                                           error:&error];

    NSString* messageServer     = [NSString base64forData:postData];
    NSString* postMessage       = [@"message=" stringByAppendingString:messageServer];
              postData          = [postMessage dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; // problem here I think

    NSString* postLength        = [NSString stringWithFormat:@"%ld",(unsigned long)[postData length]];

    NSURL*    URLToRequest      = [NSURL URLWithString:address];

    NSMutableURLRequest* semisystem = [[[NSMutableURLRequest alloc] initWithURL:URLToRequest] autorelease];

    [semisystem setHTTPMethod:@"POST"];

    [semisystem setHTTPBody:postData];
    [semisystem setValue:postLength                           forHTTPHeaderField:@"Content-Length"];
    [semisystem setValue:self.activationURL                   forHTTPHeaderField:@"EncryptionKey"];
    [semisystem setValue:messageServer                        forHTTPHeaderField:@"data"];

    NSURLResponse* response;
    NSData* data = [NSURLConnection sendSynchronousRequest:semisystem
                                         returningResponse:&response
                                                     error:&error];

    responseString2 = [NSString stringWithFormat:@"%.*s", (int)[data length], [data bytes]];
    return responseString2;
}

PHP代码：

function decrypt2($b64_data,$password)
    {
           // back to binary
            //$bin_data = mb_convert_encoding($b64_data, "UTF-8", "BASE64");
            $bin_data = base64_decode($b64_data);
            // extract salt
            $salt = substr($bin_data, 2, 8);
            // extract HMAC salt
            $hmac_salt = substr($bin_data, 10, 8);
            // extract IV
            $iv = substr($bin_data, 18, 16);
            // extract data
            $data = substr($bin_data, 34, strlen($bin_data) - 34 - 32);
            $dataWithoutHMAC = chr(2).chr(1).$salt.$hmac_salt.$iv.$data;
            // extract HMAC
            $hmac = substr($bin_data, strlen($bin_data) - 32);
            // make HMAC key
            $hmac_key = pbkdf2('SHA1', $password, $hmac_salt, 10000, 32, true);
            // make HMAC hash
            $hmac_hash = hash_hmac('sha256', $dataWithoutHMAC , $hmac_key, true);
            // check if HMAC hash matches HMAC
            if($hmac_hash != $hmac) {
                echo "HMAC mismatch".$nl.$nl.$nl;
               // return false;
            }
            // make data key
            $key = pbkdf2('SHA1', $password, $salt, 10000, 32, true);
            // decrypt
            $ret = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);      
        return $ret;
    }
$passkey = "123456";

$messageBase64                  = $_POST['message'];// THIS barely works
$messageBase64              = $_SERVER['HTTP_DATA'];// THIS WORKS
$message                = decrypt2($messageBase64,$passkey);

非常感谢提前！

Answer 1

我知道这是一个老问题，但很长一段时间我使用相同的解决方案，问题是我们在向服务器发出请求之前没有正确编码url。文档说：

  According to RFC 3986, the reserved characters in a URL are:
  reserved    = gen-delims / sub-delims
  gen-delims  = ":" / "/" / "?" / "#" / "[" / "]" / "@"
  sub-delims  = "!" / "$" / "&" / "'" / "(" / ")"
              / "*" / "+" / "," / ";" / "="

以下是如何编码字符串：/

CFStringRef encodedString =
    CFURLCreateStringByAddingPercentEscapes(
    kCFAllocatorDefault,
    (__bridge CFStringRef)(originalString),
    NULL,
    CFSTR(":/?#[]@!$&'()*+,;="),kCFStringEncodingUTF8);

再次获得字符串：

    NSString* stringEncoded = CFBridgingRelease
   (CFURLCreateWithString(kCFAllocatorDefault, encodedString, NULL));

我认为这是我们能做的最好的事情，因为我们确保字符串将被正确编码，并且在请求期间，符号不会被替换为其他东西。这里是参考：

http://developer.apple.com/library/ios/#documentation/CoreFoundation/Reference/CFURLRef/Reference/reference.html#//apple_ref/c/func/CFURLCreateStringByAddingPercentEscapes

http://developer.apple.com/library/ios/#documentation/NetworkingInternetWeb/Conceptual/NetworkingOverview/WorkingWithHTTPAndHTTPSRequests/WorkingWithHTTPAndHTTPSRequests.html

Answer 2

我刚刚找到了解决方案。在请求期间，服务器将'+'符号解释为空格，从而破坏了base64代码。以下行解决了这个问题：

postMessage       = [postMessage stringByReplacingOccurrencesOfString:@"+" withString:@"%2B"];

Answer 3

您可以在此网址

中查看已编码/已解码的字符串

http://meyerweb.com/eric/tools/dencoder/

当您按下编码按钮时，您可以看到“+”更改为“％2B”。

NSMutableURLRequest POST消息中的Base64问题？

3 个答案: