crypt a file [algorithm]

[drov]

Hello, I am trying to make a basic crypting program, you simply input a file and it's crypted using ECIES.

So I use cryptopp, ( see the function : http://www.cryptopp.com/wiki/Ellipti...ryption_Scheme ).

So I thought I just needed to open the files and crypt the content like that :

file = "lorem.txt"
			std::ifstream if1s(file);
			std::string content((std::istreambuf_iterator<char>(if1s)), std::istreambuf_iterator<char>());
			if1s.close();
			ofstream myfile1;
			myfile1.open(file);
			myfile1 << encrypt(content);
			myfile1.close();

encrypt is a custom made function to make encryption simplier here is the header :

string encrypt(string message);

This works pretty well on text files but when I try to crypt a 1 mb image, the output is 0.5 kb which obviously can't be right, so I wonder if there is some specific way to crypt some files.

Thanks in advance

[OReubens]

an std::string ends at a binary zero, which is very likely to occur in a binary file like an image.

you need to load the data into a vector/buffer, and pass that to the encryption instead of using a string.

also note that there are encryptions that are only suited to handle text. so you may also need to convert the binary into text via some encoding system like uuencode/base64/...

[Philip Nicoletti]

1) You need to open the file as binary. Otherwise, if an EOF character is encountered, input will stop.

2)

an std::string ends at a binary zero, which is very likely to occur in a binary file like an image you need to load the data into a vector/buffer, and pass that to the encryption instead of using a string.

std::string can handle embedded NULLS.