Hi Gecko,

How does the library compile when using the makefile? I suspect it may be a
path issue, but I've seen a lot of posts on gcc issues in general. Have you
gone through the archive on gcc/g++ issues?

Jeff

----- Original Message ----- 
From: "The Gecko" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, September 03, 2005 1:09 PM
Subject: Issues with SHA (or even CBC) MAC - trying to read in a file to a
buffer and MAC


Hi,

First off let me apologise if my code sytle and question are REALL lame,
I've not done any C/C++ for a long time. I've been trying to impliment a SHA
(or even CBC_MAC) for a file which I have read into a char or byte buffer.
The problem is that this thing refuses point blank to compile under Linux
(Mandrake 10.1, g++ --version is 3.41

I'm using g++ -g -msse2 -pipe codetest.cpp -o a.out where codetest.cpp is in
the same folder as everything from the unzipped crypto++ libraries.

The code is:
--------------------
#define CRYPTOPP_CBCMAC_H
//#include "stdafx.h"
#include "seckey.h"
#include "secblock.h"
#include "pch.h"
#include "cryptlib.h"
#include "cbcmac.h"
#include "sha.h"
#include "hmac.h"
#include <iostream>
#include <fstream>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "md5.h"
#include "filters.h"
#include "files.h"
#include "hex.h"
using namespace std;
using namespace CryptoPP;

int main()
{
FILE* pinfile; //Associates the pointer with a file to read in
FILE* poutfile; //and out
FILE* keyfile;
FILE* hashkey;
byte * buffery;
char * buffer2;
char filein[32];
long lSize;
int x, y;
int anykey;
byte * thekey;
byte keylength;

cout << "To hash a file press 1 + ENTER" <<std::endl;
cin >> anykey;

/***************************** ********
ENCRYPTION
*************************************/
if (anykey == 1)
{
cout << "What is the file to encrypt:" <<std::endl;
cin >> filein;

//Open the file and the key in read only mode
pinfile = fopen ( filein , "rb" );
if (pinfile==NULL) exit (1);
hashkey = fopen ( "key.txt" , "rb" );
if (hashkey==NULL) exit (1);

// obtain file size.
fseek (pinfile , 0 , SEEK_END);
lSize = ftell (pinfile);
rewind (pinfile);

fseek (hashkey , 0 , SEEK_END);
keylength = ftell (hashkey);
rewind (hashkey);

// DANGER WILL ROBINSON DANGER
// allocate memory to contain the whole file.
buffery = (byte*) malloc (lSize);
buffer2 = (char*) malloc (8);
thekey = (byte*) malloc(keylength);
if (buffery == NULL) exit (2);

// DANGER WILL ROBINSON DANGER
// whole file copied into buffer.
fread (buffery,1,lSize,pinfile);

byte * bufferzz9;
bufferzz9 = (byte*) malloc (2 * SHA::DIGESTSIZE);

HMAC<SHA > mac;
mac.SetKey(thekey, keylength);
mac.Update(buffery, lSize);
mac.Final(bufferzz9);

//TRIED WITH CBC_MAC No joy either
//CBC_MAC_Base<CBC_MAC>(thekey, keylength).CalculateDigest(bufferzz9,
buffery, lSize);
// )) or ) here?
// Clear up mess made
fclose (pinfile);
free (buffery);
free (buffer2);

}
return 0;
}
----------

The error begins:


/home/dev/cryptopp521/seckey.h:145: undefined reference to `vtable for
CryptoPP::HMAC_Base'
/home/dev/tmp/cclsTN2o.o(.gnu.linkonce.t._ZN8CryptoPP9HMAC_BaseD2Ev+0x17):
In function `CryptoPP::HMAC_Base::~HMAC_Base()':
/home/dev/cryptopp521/JpegCoder2.cpp:93: undefined reference to `vtable for
CryptoPP::HMAC_Base'
/home/dev/tmp/cclsTN2o.o(.gnu.linkonce.t._ZN8CryptoPP25SimpleKeyedTransforma
tionINS_18HashTransformationEED2Ev+0xb):
In function

And goes on for about 100 lines.

It seems tro be a linking issue as using g++ -g -msse2 -pipe -c
codetest.cpp-o
a.out produces no problems

How can I basically read in a file and generate a MAC for it. I'd like to
know both SHA and CBC_MAC really for education purposes.

Thanks

T Gecko

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