#### About PKCS#11

PKCS#11 is an API for storing and using crypto objects, and performing crypto operations on them.

It is specified at the RSA website and a handy PKCS#11 reference is also available.

## PKCS#11 URIs

PKCS#11 URIs are a standard for referring to PKCS#11 modules, tokens, or objects. What the PKCS#11 URI refers to depends on the context in which it is used.

A PKCS#11 URI can always resolve to more than one object, token or module. A PKCS#11 URI that refers to a token, would (when used in a context that expects objects) refer to all the token on that module.

To parse a PKCS#11 URI, use the `gck_uri_data_parse()` function passing in the type of context in which you’re using the URI. To build a URI, use the `gck_uri_data_build()` function.

In most cases, the parsing or building of URIs is already handled for you in the GCK library. For example: to enumerate objects that match a PKCS#11 URI use the `gck_modules_enumerate_uri()` function.