# PKCS#11 configuration

The GCR library maintains a global list of PKCS#11 modules to use for its various lookups and storage operations. Each module is represented by a `GckModule` object. You can examine this list by using `gcr_pkcs11_get_modules()`.

The list is configured automatically by looking for system installed PKCS#11 modules. It’s not not normally necessary to modify this list. But if you have special needs, you can use the `gcr_pkcs11_set_modules()` and `gcr_pkcs11_add_module()` (or `gcr_pkcs11_add_module_from_file()`) to do so.

Trust assertions are stored and looked up in specific PKCS#11 slots. You can examine this list with `gcr_pkcs11_get_trust_lookup_slots()`.