Appendix: PCC Application Identifiers

The cloud applications that run on PCC nodes and the identifiers each is known by.

Overview

A PCC node runs one or more cloud applications that handle incoming requests. Each has associated identifiers that security researchers can use to correlate software components with this guide.

The table below lists, for each application:

The application name used in this guide.
A cloud-app name, listed in the node’s configuration to select which applications the node runs.
A ServiceDiscovery registration, the string a node advertises so the Node selection can route matching requests to it.
The cryptex that distributes the application on an Apple silicon node, named by its transparency-log asset variant.
The transparency log names under which the application’s releases are published.

Application	Cloud-app name	ServiceDiscovery registration	Cryptex	Transparency log names
Statelessinference	`TIECloudApp`	`tie-cloudboard-apple-com`	`PrivateCloud Support`	`TIE`, `TIE <variant>`
Transitivetrust	`TIEProxyApp`	`trusted-proxy`	`PCCApp_TrustedProxy`	`TIE Proxy`
Pccagent	`PCCAgentApp`	`pcc-agent`	`PCCApp_TrustedProxy`	`PCC Agent`
Pccagent	`PCCAgentWorkerApp`	`pcc-agent-worker`	`PrivateCloud Support`	`PCC Agent Worker`, `PCC Agent Worker <variant>`
Mediadecoding	`PCCMediaDecoder`	`pcc-media-decode`	`PCCApp_MediaDecode`	`PCC MediaDecode`
Privatefilterservice	—	`trusted-filter`	`PCCApp_TrustedProxy`	`Private Filter Service`
Appendix_systemconfig	`NullCloudApp`	`pcc-null-app`	Various	—
Vreshadow	`ShadowTunnelCloudApp`	—	—	—
Applereferenceimage	`CIPCloudApp`	`cip-cloudboard-apple-com`	`PCCApp_Provenance`	`Provenance`
Transitivetrust	`TrampolineProxyApp`	`trampoline-trusted-proxy`	`PCCApp_TrustedProxy`	`Trampoline Proxy`

The Private Filter Service is a long-lived persistent service rather than a per-request cloud application; it has no cloud-app name and is reached through its trusted-filter ServiceDiscovery registration.
NullCloudApp is a test application used to exercise the request path without performing inference; its configuration domains appear in Appendix: Apple Silicon System Configuration.
ShadowTunnelCloudApp implements shadow tunneling, a test-only capability available in the VRE that replaces a cloud application with a lightweight gRPC proxy forwarding requests to a shadow remote that a researcher controls; it adopts the ServiceDiscovery registration of the application it shadows.
TrampolineProxyApp is a proxy application that takes the set of workloads it proxies for from configuration, rather than declaring a fixed set the way TIEProxyApp does.

The Transparency log names column shows the naming pattern for each application. For compute applications, the base name may carry a model- or workload-specific suffix, shown here as <variant>, and the set of suffixes grows as new variants are deployed. For the authoritative, current list of published releases, see Inspecting Releases.

On a Google Cloud node, an application ships inside the Workload Megacontainer rather than in a cryptex, so the Cryptex column above does not apply; the measured PCC_VARIANT configuration value selects which of the image’s variants a node runs. The inference application runs there as tie-cloud-app, and it advertises the same tie-cloudboard-apple-com ServiceDiscovery registration.