PKCS5_PBKDF2_HMAC_SHA1

pbkdf2.c

#include <stdio.h>
#include <string.h>

#include <openssl/x509.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>

int main(int argc, char *argv[])
{
	char pass[1024];	// passphrase read from stdin
	char salt[1024];	// salt
	char result[1024];	// result
	int salt_len;		// salt length
	int ic;			// iteration counter

	FILE *fp;

	if (argc != 3) {
		fprintf(stderr, "usage: %s salt_file iteration < passwd_file > binary_key_file\n", argv[0]);
		exit(1);
	}

	ic = atoi(argv[2]);

	fp = fopen(argv[1], "r");
	if (!fp) {
		fprintf(stderr, "error opening salt file: %s\n", argv[1]);
		exit(2);
	}

	salt_len = fread(salt, 1, sizeof(salt), fp);

	fclose(fp);		

	fgets(pass, 1024, stdin);
	
	if (pass[strlen(pass)-1] == '\n')
		pass[strlen(pass)-1] = '\0';

	PKCS5_PBKDF2_HMAC_SHA1(pass, strlen(pass), (const unsigned char *) salt, salt_len, ic, 16, (unsigned char *) result);

	fwrite(result, 1, 16, stdout);

	return 0;
}