DCAP quote provider using the Intel Trusted Services API as a backend. This crate compiles into `libdcap_quoteprov.so`, which is needed as a backend when using `libsgx_dcap_ql`. To use this library, the dynamic linker needs to be able to find it. This means you should install it in your system's library path or set the `LD_LIBRARY_PATH` environment variable. You must set your API key in the `OCP_APIM_SUBSCRIPTION_KEY` environment variable. You can sign up for a service subscription at https://api.portal.trustedservices.intel.com/. SGX: Software Guard Extensions DCAP: DataCenter Attestation Primitives QL: Quoting Library