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Crypto using Libtom with ECDSA

Hi,
I am doing a project using the Libtom library to sign sections of a portable executable with ECDSA signature in C language.
I downloaded the doc of libtom but i don't understand anything about the functions and parameters. I just have to understand how to use the library.
Someone can help me to find tutorials and docs more easy to read.
Thanks

ASKER CERTIFIED SOLUTION

btan

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btan

Also you can find some test codes
https://github.com/libtom/libtomcrypt/tree/master/testprof

Wathan

ASKER

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;

	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

"yarrow_prng" is not declared in the main function.
So have to check the header file such as tomcrypt.h.
Suggest you open a new question thanks

Wathan

ASKER

Now i have a problem in compiling:

Error      7      error LNK2019: unresolved external symbol _sha1_init referenced in function _hashSHA1      D:\Dropbox\ProjSecSoft\Siger\Siger\Main.obj      Siger
Error      8      error LNK2019: unresolved external symbol _sha1_process referenced in function _hashSHA1      D:\Dropbox\ProjSecSoft\Siger\Siger\Main.obj      Siger
Error      9      error LNK2019: unresolved external symbol _sha1_done referenced in function _hashSHA1      D:\Dropbox\ProjSecSoft\Siger\Siger\Main.obj      Siger
Error      10      error LNK2001: unresolved external symbol _sha1_desc      D:\Dropbox\ProjSecSoft\Siger\Siger\Main.obj      Siger
Error      11      error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup      D:\Dropbox\ProjSecSoft\Siger\Siger\MSVCRTD.lib(crtexew.obj)      Siger
Error      12      error LNK1120: 5 unresolved externals      D:\Dropbox\ProjSecSoft\Siger\Debug\Siger.exe      Siger
Error      13      error C1083: Cannot open include file: 'tommath.h': No such file or directory      d:\downloads\compressed\libtom\libtomcrypt-1.17\src\math\ltm_desc.c      17      1      libtomcrypt