So far, I knew that traditional HSMs (Hardware Security Module) can be used to store key of a single user. But, recently, I came to know that newer HSMs have the capability to store keys of multiple users and let users use those keys to sign documents. Newer HSMs does this using Subscriber Authentication Module (SAM). But I could not find any useful information about it.
Can somebody help me understand more? Can somebody give pointers to how HSMs with SAM can be used for storing keys of multiple users and signing using those keys?