* kube-apiserver: the OpenID Connect authenticator can now verify ID Tokens signed with JOSE algorithms other than RS256 through the --oidc-signing-algs flag. ([#58544](https://github.com/kubernetes/kubernetes/pull/58544), [@ericchiang](https://github.com/ericchiang))

* Laid the groundwork for OIDC distributed claims handling in the apiserver authentication token checker. A distributed claim allows the OIDC provider to delegate a claim to a separate URL. ([ref](http://openid.net/specs/openid-connect-core-1_0.html#AggregatedDistributedClaims)). ([#63213](https://github.com/kubernetes/kubernetes/pull/63213), [@filmil](https://github.com/filmil))

* The OpenID Connect authenticator can now use a custom prefix, or omit the default prefix, for username and groups claims through the --oidc-username-prefix and --oidc-groups-prefix flags. For example, the authenticator can map a user with the username "jane"...

* API server authentication now caches successful bearer token authentication results for a few seconds. ([#50258](https://github.com/kubernetes/kubernetes/pull/50258), [@liggitt](https://github.com/liggitt))

- The alpha feature `ServiceAccountIssuerDiscovery` enables publishing OIDC discovery information and service account token verification keys at `/.well-known/openid-configuration` and `/openid/v1/jwks` endpoints by API servers configured to issue service account tokens. ([#80724](https://github.com/kubernetes/kubernetes/pull/80724), [@cceckman](https://github.com/cceckman)) [SIG API Machinery, Auth, Cluster Lifecycle and Testing]...

### Auth

- Fixed OpenID Connect (OIDC) token refresh when the client secret contains a special character. ([#76914](https://github.com/kubernetes/kubernetes/pull/76914), [@tsuna](https://github.com/tsuna))

* Support whitespace in command path for gcp auth plugin ([#41653](https://github.com/kubernetes/kubernetes/pull/41653), [@jlowdermilk](https://github.com/jlowdermilk))
* client-go no longer imports GCP OAuth2 and OpenID Connect packages by default. ([#41532](https://github.com/kubernetes/kubernetes/pull/41532), [@ericchiang](https://github.com/ericchiang))