The first character after the user name in /etc/shaddow, is the type of encryption used.
http://www.lamolabs.org/blog/10670/how-is-my-password-stored-in-linux/
So:
$5$ means SHA256
$6$ means SHA512
Looking at my cent 5.9 vm I downloaded from puppet's website, I notice that the encryption level is $1$.
What level of encryption is 1 ?
[root@learn etc]# cat /etc/shadow| grep root | cut -c1-8
root:$1$
Resources
http://linux.die.net/man/3/crypt