Key rotator (#3136)

Supports #2147.

Introduces the `key_rotator`, which is a utility for managing the lifecycle of global HPKE keys. It will bootstrap keys, and rotate them according to the rotation policy in the config.

Keys are unique by their HPKE ciphersuite. For each ciphersuite, a key is run through the pending->active->expired->deleted lifecycle. It is permissive of some manual operator changes, e.g. if a manual key rotation needs to be executed through janus_cli or the aggregator API.

In this iteration, it runs as a standalone binary for use in a cronjob. It is suitable for deployment in our environments, including taskprov ones. A future PR will add support for BYOH deployments by letting the `aggregator` process run the key rotator.

Cargo.toml

@@ -77,6 +77,8 @@ pretty_assertions = "1.4.0"
 prio = { version = "0.16.5", default-features = false, features = ["experimental"] }
 prometheus = "0.13.4"
 querystring = "1.1.0"
+quickcheck = { version = "1.0.3", default-features = false }
+quickcheck_macros = "1.0.0"
 rand = "0.8"
 rayon = "1.10.0"
 reqwest = { version = "0.12.5", default-features = false, features = ["rustls-tls"] }

aggregator/Cargo.toml

@@ -115,6 +115,8 @@ janus_aggregator_core = { workspace = true, features = ["test-util"] }
 mockito = { workspace = true }
 opentelemetry_sdk = { workspace = true, features = ["testing"] }
 prio = { workspace = true, features = ["multithreaded"] }
+quickcheck = { workspace = true }
+quickcheck_macros = { workspace = true }
 rstest.workspace = true
 tempfile = { workspace = true }
 tokio = { workspace = true, features = ["net", "test-util"] } # ensure this remains compatible with the non-dev dependency

aggregator/src/aggregator.rs

@@ -129,6 +129,7 @@ mod collection_job_tests;
 mod error;
 pub mod garbage_collector;
 pub mod http_handlers;
+pub mod key_rotator;
 pub mod problem_details;
 pub mod query_type;
 pub mod report_writer;