myvtm/Module/mod_cardswiper/kdf.h

#include <memory.h>
#include <openssl/evp.h>
#include "sm3.h"
// ----- KDF FUNCTIONS START -----
//typedef void *(*KDF)(const void *in, size_t inlen, void *out, size_t *outlen);

int x9_63_kdf(const EVP_MD *md, const unsigned char *share, size_t sharelen, size_t keylen, unsigned char *outkey)
{
	int ret = 0;

	EVP_MD_CTX ctx;
	unsigned char counter[4] = {0, 0, 0, 1};
	unsigned char dgst[EVP_MAX_MD_SIZE];
	unsigned int dgstlen;
	int rlen = (int)keylen;
	unsigned char * pp;

	pp = outkey;

	if (keylen > (size_t)EVP_MD_size(md)*255)
	{
		fprintf(stderr, "%s(%d):", __FILE__, __LINE__);
		goto end;
	}

	while (rlen > 0)
	{
		EVP_MD_CTX_init(&ctx);

		if (!EVP_DigestInit(&ctx, md))
		{
			fprintf(stderr, "%s(%d):", __FILE__, __LINE__);
			goto end;
		}

		if (!EVP_DigestUpdate(&ctx, share, sharelen))
		{
			fprintf(stderr, "%s(%d):", __FILE__, __LINE__);
			goto end;
		}
		if (!EVP_DigestUpdate(&ctx, counter, 4))
		{
			fprintf(stderr, "%s(%d):", __FILE__, __LINE__);
			goto end;
		}
		if (!EVP_DigestFinal(&ctx, dgst, &dgstlen))
		{
			fprintf(stderr, "%s(%d):", __FILE__, __LINE__);
			goto end;
		}

		EVP_MD_CTX_cleanup(&ctx);

		memcpy(pp, dgst, keylen>=dgstlen ? dgstlen:keylen);

		rlen -= dgstlen;
		pp += dgstlen;
		counter[3]++;
	}

	ret = 1;

end:
	return ret;
}

int sm3_kdf(unsigned char *share, size_t sharelen, size_t keylen, unsigned char *outkey)
{
	int ret = 0;
	
	unsigned char counter[4] = {0, 0, 0, 1};
	unsigned char dgst[EVP_MAX_MD_SIZE];
//	unsigned char ZA[33] = "\x3B\x85\xA5\x71\x79\xE1\x1E\x7E\x51\x3A\xA6\x22\x99\x1F\x2C\xA7\x4D\x18\x07\xA0\xBD\x4D\x4B\x38\xF9\x09\x87\xA1\x7A\xC2\x45\xB1";
//	unsigned char ZB[33] = "\x79\xC9\x88\xD6\x32\x29\xD9\x7E\xF1\x9F\xE0\x2C\xA1\x05\x6E\x01\xE6\xA7\x41\x1E\xD2\x46\x94\xAA\x8F\x83\x4F\x4A\x4A\xB0\x22\xF7"; 
	unsigned int dgstlen;
	int rlen = (int)keylen;
	unsigned char * pp;
	sm3_context sm3_ctx;
	pp = outkey;
	
	if (keylen > 16*255)
	{
		fprintf(stderr, "%s(%d):", __FILE__, __LINE__);
		goto end;
	}
	
	while (rlen > 0)
	{
		sm3_starts(&sm3_ctx);
		sm3_update(&sm3_ctx,share,sharelen);
		sm3_update(&sm3_ctx,counter,4);
		sm3_finish(&sm3_ctx,dgst);
		dgstlen = 32;

		memcpy(pp, dgst, keylen>=dgstlen ? dgstlen:keylen);
		
		rlen -= dgstlen;
		pp += dgstlen;
		counter[3]++;
	}
	
	ret = 1;
	
end:
	return ret;
}
// ----- KDF FUNCTIONS END -----