When configuring SNMPv3 Users under the settings under, "Maintenance > SNMP > SNMPv3 Users":

A requirement to know the version of SHA when using SNMPv3 Users authentication parameters has come up. 

The SHA version is SHA1. This is true for SGOS 6.6 and 6.7.

Below is the hash function size for the authentication security  users in SNMPv3 for MD5 and SHA and also the key length for AES which is 128:

SNMP HMACMD5 128
SNMP HMACSHA1 160
SNMP AES 128

For now, these settings are not configurable. A feature request can be processed to increase the priority of changing these parameters to something like SHA2.

For more details on AES refer to TECH243260