删除bmp标头进行加密 [英] Remove bmp header to encrypt

问题描述

我对C＃来说很新，并且已经在图像上交付了这个AES加密项目。这可能是一个非常简单的事情，我在这里错过。我正在尝试从bmp中删除头文件，然后对其余部分进行加密，然后将头添加回来。如果我不删除标题，程序运行良好。要删除，我试过这个（bmp头是54字节）：

  MyImage = new Bitmap（path）; 
 MemoryStream ms = new MemoryStream（）; 
 
 MyImage.Save（ms，System.Drawing.Imaging.ImageFormat.Bmp）; 
 
 byte [] Header = null，picture = null，pictureFull = ms.ToArray（）; （int i = 0; i< pictureFull.Length; i ++）
 {
 if（i <54）
 {标题[i] = pictureFull [i]; } 
 else 
 {picture [i  -  54] = pictureFull [i]; } 
} 
 
 
 byte [] demoKeyBytes = new byte [] {0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a， 0x0b，0x0c，0x0d，0x0e，0x0f}; 
 
 PaddingMode padding = PaddingMode.ISO10126; 
 
 EncryptedImg = EncryptCall（demoKeyBytes，padding，picture）; 
  

问题是，如果我尝试继续加密和解密图片，我得到一个空值。如果我继续使用完整的图像pictureFull进行enc / dec，我也会得到一个空值。我需要完全删除FOR，以使程序能够正常地进行enc / decpictureFull，尽管FOR甚至不修改它。有没有其他方法可以保存byte []数组或出了什么问题？

解决方案

byte [] 是一个对象，所以您不想将该类型的变量初始化为 null 。您可能想要初始化标题，如下所示：

  byte []标题=新字节[54]; 
  

和图片到新字节[] ，其长度至少等于实际图像数据长度，如下所示：

  byte [] picture = new byte [pictureFull.Length  -  54]; 
  

然后你可以复制东西给他们。

I'm pretty new to C# and got handed this AES encryption project on images. There's probably a very simple thing that I'm missing here. I'm trying to remove the header from a bmp and encrypt the rest then add the header back. If I don't remove the header the program works well. To remove, I tried this (bmp header is 54 bytes):

MyImage = new Bitmap("path");
MemoryStream ms = new MemoryStream();

MyImage.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);

byte[] Header=null, picture=null, pictureFull = ms.ToArray();


for (int i = 0; i < pictureFull.Length; i++)
{
    if (i < 54)
    { Header[i] = pictureFull[i]; }
    else 
    { picture[i - 54] = pictureFull[i]; }
}


byte[] demoKeyBytes = new byte[] {  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f};

PaddingMode padding = PaddingMode.ISO10126;

EncryptedImg = EncryptCall(demoKeyBytes, padding, picture);

The problem is that if i try to go on and encrypt and decrypt "picture" I get a null value. I also get a null value if i go on to enc/dec with the full image "pictureFull". I need to completely remove the FOR in order for the program to enc/dec normally "pictureFull", although that FOR doesn't even modify it. Is there some other way to save byte[] arrays or what's wrong?

解决方案

byte[] is an object, so you don't want to initialize a variable of that type to null. You probably want to initialize Header like this:

byte[] Header = new byte[54];

and picture to a new byte[] with length at least equal to the actual image data length, like this:

byte[] picture = new byte[pictureFull.Length - 54];

Then you can copy things to them.

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