urgent help:hash function

jack · #1 15-Mar-2004, 23:41

Hi can anyone provide me with a simple hash function that takes values for e.g numbers and alphabets. let say
int i =23544564;
char a= jack;
int j=123;
int x= 202.020.22.0

and convert it to return a hash string like as4546wui

thanx
jack

aaroncohn · #2 15-Mar-2004, 23:49

Looks like you're in the wrong place. This is a forum designed to help people solve problems. If you're looking for source code, you might want to check out this website:

http://www.sourceforge.net

dsmith · #3 03-Apr-2004, 21:20

Jack, you can't receive PM's because your mail account is filled up, so I posted a reply to you here, since it is a similar question and hopefully you will get an email message about a post.

Quote:

Originally Posted by jack

hi can you provide me a simple example to do a hash with md5 in C
thanx.
jack

Hi Jack.

I don't know much of anything about md5. I put together this simple sample, but I have no idea if it works right or not. If you know what you are trying to do this might get you started. Please note that you will need the openssl libraries.

CPP / C++ / C Code:

include <openssl/md5.h>
#include <stdio.h>

int main()
{
	char 	string[100];
	char*	hash = 0;
	
	printf("Enter string to hash: ");
	fgets(string,100,stdin);
	hash = MD5(string,strlen(string),hash);
	
	printf("The hash is: %s\n",hash);

	return 0;
}

When you compile you need to link with the ssl library. In gcc I did:

Code:

gcc md5.c -lssl -o md5

Hope this gets you started.

dsmith · #4 04-Apr-2004, 09:29

Try this instead. The hash seems to work okay, it was the way that I was printing it that gave the difference. I get the exact same thing using md5sum as I do using this.

CPP / C++ / C Code:

#include <openssl/md5.h>
#include <stdio.h>

int main()
{
	char 	string[100];
	unsigned char*	hash = 0;
	unsigned char*	parse;
	
	printf("Enter string to hash: ");
	fgets(string,100,stdin);
	hash = MD5(string,strlen(string),hash);
	
	printf("The hex hash value is: ");
	parse = hash;
	while(*parse){
		printf("%02x",*parse);
		parse++;
	}
	printf("\n");
	
	return 0;
}

dsmith · #5 05-Apr-2004, 08:47

Dave. If you are using *nix, you should try pulling up the man page for md5. It should tell you everything about the function that you want to know. Here is the basic format of MD5:

Quote:

unsigned char *MD5(const unsigned char *d, unsigned long n,unsigned char *md)

So while

CPP / C++ / C Code:

 
hash = MD5(string,strlen(string),hash);

will hash the entire string, using

CPP / C++ / C Code:

hash = MD5(string,8,hash);

will hash only the first 8 characters of the string.

Also, could you please respond back in this thread? It is kind of a pain to do this through PM's and it makes me look like I am adding comments to this thread for the fun of it.

cheers,
d

aaroncohn · #6 05-Apr-2004, 13:18

I think I might have scared him away

??:

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