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Crypto using Libtom with ECDSA

Hi,
In the ecc_test.c how does tom use yarrow_prng (line 223) without initialize it?
I copied his code from line 218 to 230 as is, trying to sign a hashed charstream but Visual Studio tell me that there is an error yarrow_prng undeclared identifier.
Below is my code:

#include<stdio.h>
#include<tomcrypt.h>

void main()
{
	unsigned long x;
	unsigned char buf[4][4096];
	int stat, stat2;
	ecc_key usera, userb, pubKey, privKey;
	//prng_state yarrow_prng;

	for (x = 0; x < 16; x++) {
		buf[0][x] = x;
	}
	x = sizeof (buf[1]);
	ecc_sign_hash (buf[0], 16, buf[1], &x, &yarrow_prng, find_prng ("yarrow"), &privKey);
	ecc_verify_hash (buf[1], x, buf[0], 16, &stat, &pubKey);
	buf[0][0] ^= 1;
	ecc_verify_hash (buf[1], x, buf[0], 16, &stat2, &privKey);
	if (!(stat == 1 && stat2 == 0)) { 
		fprintf(stderr, "ecc_verify_hash failed %d, %d, ", stat, stat2);
	}
}

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btan

can try uncomment this line below e.g. remove the "//" suffix (exclude the quotes).

//prng_state yarrow_prng;

the "tomcrypt.h" should have include of "tomcrypt_prng.h"
the "tomcrypt_prng.h" should have something as below

#ifdef LTC_YARROW
struct yarrow_prng {
int cipher, hash;
unsigned char pool[MAXBLOCKSIZE];
symmetric_CTR ctr;
LTC_MUTEX_TYPE(prng_lock)
};
#endif

typedef union Prng_state {
char dummy[1];
#ifdef LTC_YARROW
struct yarrow_prng yarrow;
#endif
#ifdef LTC_RC4
struct rc4_prng rc4;
#endif
#ifdef LTC_FORTUNA
struct fortuna_prng fortuna;
#endif
#ifdef LTC_SOBER128
struct sober128_prng sober128;
#endif
} prng_state;

Wathan

ASKER

when i uncomment this line, 4 externals erors appears

btan

Using the the entire LibTomCrypt source, you would have built a library file with Visual Studio 2010 which compiles without issue. The error is likely due to your simple test console application that links the with TomCrypt library, hence receive a linker error.

Some try the debug library build which may works with the test code. However, the release build of tomcrypt.lib seems to be always missing some symbols as in your case. The project configs for visual studio may include custom steps for building
e.g. - crypt_find_prng.c
(http://libtomcrypt.sourcearchive.com/documentation/1.17-3.1/crypt__find__prng_8c_a53cfb5c7551b314e634a08e8be20a69c.html)
Likewise for
-libtomcrypt/src/pk/ecc/ecc_sign_hash.c and
-libtomcrypt/src/pk/ecc/ecc_verify_hash.c

Using gcc to build this code with the static library may not work. Also likely for variable flagged also need to add those into the makefile's CFLAGS and CPPFLAGS variables so the headers will declare those variable as an extern variable....

btan

I saw your other posting in previous - did you tried the debug version? if that is alright then have to check it makefile build configurations which are not avail in the release makefile build.

Also there are 5 different library besides the libtomcrypt, such as libtommath, tomsfastmath, libtomfloat and libtompoly. @ http://libtom.

Also I believe there is some VS solution file in github

Wathan

ASKER

Can you explain me exactly what do i have to do to use libtomcrypt and libtommath in my project? What is, step by step, the way from the creation of my project to the using of the libtom libraries?

btan

Using the the entire LibTomCrypt source, you should have built a library file with Visual Studio (using the "makefile.msvc" which is used for VS 6) to create a
>"tomcrypt.lib" (lib /out:tomcrypt.lib $(OBJECTS))
>"tommath.lib" (lib /out:tommath.lib $(OBJECTS))

These above Libs can then be linked into the your main project file as static library.
I afraid there is not much steps written in open for VS...
http://msdn.microsoft.com/en-us/library/ms235627.aspx#BKMK_CreateAppToRefTheLib

In case you need to run nmake to build your project using the makefile.
http://msdn.microsoft.com/en-us/library/txcwa2xx(v=vs.90).aspx
http://msdn.microsoft.com/en-us/library/a23f7tc4(v=vs.90).aspx

Fyi, I believe there are also other who has created libtomcrypt_VS2005.sln. libtomcrypt_VS2005.vcproj. libtomcrypt_VS2008.sln. libtomcrypt_VS2008.vcproj (need to googled it), similarly I saw there is for libtommath. They may be used

Do note in crypt.pdf, its chapter 13 talks about the compiling and building but for gcc.
https://github.com/libtom/libtomcrypt

As of v1.06 of the library, the build process has been moved to
two steps for the typical LibTomCrypt application. This is because
LibTomCrypt no longer provides a math API on its own and relies
on third party libraries (such as LibTomMath, GnuMP, or TomsFast-
Math).

The build process now consists of installing a math library first,
and then building and installing LibTomCrypt with a math library
configured. Note that LibTomCrypt can be built with no internal
math descriptors.

Wathan

ASKER

I don't understand the first step, how can i transform the project libtmmath to library? I do Open an existing project?

btan

You need to download libtommath from the original site https://github.com/libtom, and compile it using the makefile as you did for libtomcrypt. There is existing sln and vproj too in that download. With the two tommath.lib and tomcrypt.lib, linked them into your main project.

Wathan

ASKER

For libtomcrypt i didn't use makefile but Additionnal include directories.
Can you explain how to use makefile?

Wathan

ASKER

I succeed to make the tommath.lib and tomcrypt.lib files, so now how can i do to use them and their function in another project??
I tried to creat an other project in the same solution and i already do the references (as explained in msdn) and the include file attribution, and i receive an ERROR 1083 that saying me it can't open the header file of libtom (both of them, tommath and tomcrypt of course).

ASKER CERTIFIED SOLUTION

btan

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