CryptDecode with modifier CRYPT_ARCH_ZIP - How to use?

[Vasiliy Sokolov]

The actual question is this. As I understand it, we are talking about packing/unpacking zip array. It's mega useful thing, but I can't use it, CryptDecode function stubbornly gives zero result on test zip archive:

//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//---
   uchar array[];
   uchar key[]={0};
   uchar result[];
   int handle = FileOpen("link.zip", FILE_READ|FILE_BIN|FILE_COMMON);
   FileReadArray(handle, array);
   FileClose(handle);
   int d = CryptDecode(CRYPT_ARCH_ZIP, array, key, result);
   printf(GetLastError());
   printf("Read totals: " + (string)ArraySize(array));
  }

Maybe something else must be specified as a key, or I've got wrong idea about CRYPT_ARCH_ZIP modifier value. In any case, the documentation doesn't contain an example of the function, which makes it difficult to understand how it works. The GetLastError function writes 4001 - Unexpected Internal Error.

[Alexandr Bryzgalov]

C-4:

The actual question is this. As I understand it, we are talking about packing/unpacking zip array. It's mega useful thing, but I can't use it, CryptDecode function stubbornly gives zero result on test zip archive:

Maybe something else must be specified as a key, or I've got wrong idea about CRYPT_ARCH_ZIP modifier value. In any case, there is no example of how to use the function in the documentation, which makes it much more difficult to understand how it works. The GetLastError function writes 4001 - Unexpected Internal Error.

wrong approach

[Vasiliy Sokolov]

sanyooooook:
not the right approach

More details if you can.

[Alexandr Bryzgalov]

A ZIP archive is a whole structure, but the function archives/unarchives an array, i.e. only an array ready for unarchiving should be placed there.

Roughly speaking, it unarchives only the output of the archiving function.

[Alexandr Bryzgalov]

C-4:
More details if you can.

Or what in

link.zip

has been created by the archive function?

[Vasiliy Sokolov]

sanyooooook:

A ZIP archive is a whole structure, but the function archives/unarchives an array, i.e. only an array ready for unarchiving should be placed there.

Roughly speaking, it unarchives only the output of the archiving function.

Got it. MQ style. The main thing though is to decrypt the zip. Doesn't anyone happen to have a library for working with zip archives in MQL?

[Vasiliy Sokolov]

sanyooooook:
or what in
was created by the archive function?

Nah, it says zero. CryptDecode decodes zip. Tried to create a zip archive - CryptEncode's responses don't match those of the regular archivers. CryptEncode's zipped file is much shorter, which indirectly confirms your theory!

[Alexandr Bryzgalov]

here is a description of the file structure http://blog2k.ru/archives/3391

[Alexandr Bryzgalov]

C-4:
Nope, it says zero. CryptDecode decodes zip. I tried to create a zip archive, CryptEncode and normal archivers didn't match. CryptEncode makes the zipped file much shorter, which indirectly confirms your theory!

It's not a theory, it's just that they're used to having everything ready to go in the archiver,

I foolishly thought it would unzip files made with a normal archiver.

[Vasiliy Sokolov]

The problem is that I can't find the byte array occurrences given by CryptEncode in the regular zip archive.

The file is the same. So in a classic zip archive, there should be a byte-array corresponding to the CryptEncode byte-array

[Alexandr Bryzgalov]

C-4:

The problem is that I can't find the byte array occurrences given by CryptEncode in a normal zip archive.

), so you're looking in the wrong way.