what encription alg does my box uses
 

how can i find out what encriptyon algorithm crypts my /etc/shadow password file

I believe the algorithms most commonly used include a DES-based algorithm (see 'man crypt') and the MD5 one-way hash function (which is more secure). Check out the Shadow Password HOWTO for some details.

i`m trying to create an adduser php. I`m asking this because i saw that the adduser -p requests a crypt password. Does the crypt function in php work with this ?
thanx