C++ && md5sum's

[JNowka]

I am wondering if there are any header files for C++ to deal with md5 sums. I have not worked with md5 sums before, and am unsure how to go about this. I just want to convert a password into a md5 sum for security reasons. I don't want to do this using a file, because I am unsure if this will change the md5sum, so using md5sum that comes with Ubuntu is possibly useless. Any help will be much appreciated.

Thank you.

[duff]

ftp://mirror.cs.wisc.edu/pub/mirrors/ghost/packages/md5.tar.gz

[amo-ej1]

The easiest would be to steal (did i say steal ? i meant borrow ;-) ) some code from passwd:


apt-get source passwd

Which contains this function:



char *pw_encrypt (const char *clear, const char *salt)
{
static char cipher[128];
char *cp;

cp = crypt (clear, salt);
if (!cp) {
/*
* Single Unix Spec: crypt() may return a null pointer,
* and set errno to indicate an error. The caller doesn't
* expect us to return NULL, so...
*/
perror ("crypt");
exit (1);
}
if (strlen (cp) != 13)
return cp; /* nonstandard crypt() in libc, better bail out */
strcpy (cipher, cp);

return cipher;
}


This relies on man 3 crypt from the libc6 package (so a basic library readily available, remember to link with -lcrypt).

[amo-ej1]

Oh yeah, and in the same manpage, all the way down:



The glibc2 version of this function has the following additional fea‐
tures. If salt is a character string starting with the three charac‐
ters "$1$" followed by at most eight characters, and optionally termi‐
nated by "$", then instead of using the DES machine, the glibc crypt
function uses an MD5-based algorithm, and outputs up to 34 bytes,
namely "$1$<string>$", where "<string>" stands for the up to 8 charac‐
ters following "$1$" in the salt, followed by 22 bytes chosen from the
set [a–zA–Z0–9./]. The entire key is significant here (instead of only
the first 8 bytes).

[tasos]

man 3 crypt does not return the man page..
is there an extra package libc6-doc or something?
thanx

[wolfbone]

Primary documentation for glibc is in texinfo format, not man pages.

[geirha]

Install the manpages-dev package. At least the man-page for crypt is there

[tasos]

Thanx geirha..that did the trick ;)