topic Crypt in Operating System - HP-UX

Crypt

Mauro Gatti — Wed, 04 Sep 2002 11:15:34 GMT

Hi all,
I'd like to create a little C program that use the same crypt algorithm of passwd command.
The program must accept one argument that is the word to crypt and must return the encrypted word.

Do You could give me an Idea to do it?

Re: Crypt

Bill McNAMARA_1 — Wed, 04 Sep 2002 11:16:58 GMT

man crypt ?

Later,
Bill

Re: Crypt

Mauro Gatti — Wed, 04 Sep 2002 11:37:48 GMT

I've already tried but crypt command do not use the same algorythm of passwd.
I've found in man 3c crypt the crypt() function but I'd like to see some example to understand how use it.

Re: Crypt

A. Clay Stephenson — Wed, 04 Sep 2002 12:52:07 GMT

It's actually easy:

1) Extract the 1st two characters of the existing password (old_passwd) hash - this is the 'salt'.

2) char *passwd2 = crypt(plaintext,salt);

3) if (strcmp(old_passwd,passwd2) == 0)
{
printf("Password okay\n");
}

When choosing a new password, you are advised to create a new salt value. The attached snippet will prove useful.

Re: Crypt

Jack Tan — Thu, 05 Sep 2002 12:16:33 GMT

Be aware that passwords longer than 8 characters should be encrypted on trusted HP-UX using bigcrypt() instead of crypt(). On other platforms, other functions are used besides bigcrypt(), such as dispcrypt() on Tru64.

If you need a cross-platform solution, I'd suggest looking at the source code to sudo (http://www.courtesan.com/sudo/) and wu-ftpd (http://www.wu-ftpd.org/).