The supported hashing algorithms are DES, MD5, SHA256, SHA512, and Blowfish but the default is SHA512
Hashes that start with $6$ are indicative of SHA512
The settings are found in /etc/login.conf where :passwd_format=sha512:\ declares the preferred hashing algorithm
In order to change the hashing method execute cap_mkdb /etc/login.conf. It will only affect the new passwords. The old ones need to be re-hashed by asking users to run passwd in order to change their password
/root 