md5 encoding

[jby1]

Hi

I am looking for a function to provide me with md5 encoding. Is there anything in the standard C libraries to do this? (I haven't used C for some years so I am a little rusty!)

Cheers

 

[Salem]

> I am looking for a function to provide me with md5 encoding
A quick "google" for "md5 source code" found

http://www.cr0.net:8040/code/crypto/md5.php

> Is there anything in the standard C libraries to do this?
Nope

 

[AllenV]

Actually you should check the

http://www.openssl.org

project, as it includes MD5 hash capabilities and more importantly has good documentation.

On the other hand, the code that Salem has pointed to is extremely well exampled, and could be easily modified to do MD5 password comparing suitable for Linux or LDAP password authentication.

 

[dlkfjdlkfjdlfkd]

RFC 1321 includes an implementation.

 

[AllenV]

Not to beat a dead horse, but since many people may actually want to do passwd file auth under Linux specifically - crypt() will handle the special case of salted MD5 as well as traditional crypt. Strangely my system's shadow file has both traditional and SMD5. Here's a code sample from I ended up using:

+++snip+++
char *userlogin; // From function call
char *userpassword; // From function call
char shadowpass[1024] = "";
char buffer[1024] = "";
char usrSalt[100] = "";
char *saltmine = NULL;
int saltlen = 0;

// ... Getting password from shadow removed ...

if (0 == strncmp(shadowpass, "$1$", 3))
{
saltmine = strchr(&shadowpass[3], '$');
saltlen = 1 + (saltmine - shadowpass);

strncpy(usrSalt, shadowpass, saltlen);
usrSalt[saltlen] = 0;
}
else
{
strncpy(usrSalt, shadowpass, 2);
usrSalt[2] = 0;
}
strncpy( buffer, crypt(usrpasswd, usrSalt), BUFSIZ);

// Zero if match: - strcmp(buffer, shadowpass)
+++snip+++

I hope this makes someone's life easier!