/*
 * Example: PBKDF2-SHA256 in libgcrypt
 */
#include <stdio.h>
#include <string.h>
#include <openssl/evp.h>
#include <openssl/rand.h>

/* Print buffer in HEX with optional separator */
static void hexprint(const char *d, int n, const char *sep)
{
	int i;

	for (i = 0; i < n; i++)
		printf("%02hhx%s", (const char)d[i], sep);
	printf("\n");
}

static void print_out(const char *hash_type, const void *out, unsigned int out_len, const int iteration, const char *password, const char *salt, const double c)
{
	printf("Derived key using %i vector. %s (P=%s, S=%s, c=%d, dkLen=%i)", iteration, hash_type, password, salt, c, out_len);
	hexprint((const char*)out, out_len, " ");
}

int main(int argc, char *argv[])
{
	const char *passwords[] = {"password", "password", "password", "password", "passwordPASSWORDpassword", "pass\0word"};
	const char *salts[] = {"salt", "salt", "salt", "salt", "saltSALTsaltSALTsaltSALTsaltSALTsalt", "sa\0lt"};
	const double iterations[] = {1, 2, 4096, 16777216, 4096, 4096};
	const int out_lens[] = {20, 20, 20, 20, 25, 16};

        /* Library initialization */
        OpenSSL_add_all_algorithms();
        printf("OpenSSL (%s):\n", SSLeay_version(SSLEAY_VERSION));

	printf("PBKDF2-SHA1 using OpenSSL:\n");

	int i;
	for (i = 0; i < 6; i++ ) {
		unsigned char key[iterations[i]];
		if (!PKCS5_PBKDF2_HMAC(passwords[i], strlen(passwords[i]), salts[i], sizeof(salts[i]),
			iterations[i], EVP_sha1(), sizeof(key), key));
			return 2;

		print_out("PBKDF2-SHA1", key, sizeof(key), i, passwords[i], salts[i], iterations[i]);
	}

	for (i = 0; i < 6; i++ ) {
		unsigned char key[32];
		if (!PKCS5_PBKDF2_HMAC(passwords[i], strlen(passwords[i]), salts[i], sizeof(salts[i]),
			iterations[i], EVP_sha256(), sizeof(key), key));
			return 2;

		print_out("PBKDF2-SHA256", key, sizeof(key), i, passwords[i], salts[i], iterations[i]);
	}


	return 0;
}