- Structured Authentication Configuration now supports configuring multiple JWT authenticators. The maximum allowed JWT authenticators in the authentication configuration is 64. ([#123431](https://github.com/kubernetes/kubernetes/pull/123431), [@aramase](https://github.com/aramase))

* 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))

* 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 JWT authenticator in `kube-apiserver` now reports the following metrics when the `StructuredAuthenticationConfiguration` feature gate is enabled:
  - `apiserver_authentication_jwt_authenticator_jwks_fetch_last_timestamp_seconds`

* 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" to "google:jane" by supplying the "google:" username prefix. ([#50875](https://github.com/kubernetes/kubernetes/pull/50875),...

* kube-apiserver: OIDC authentication now supports requiring specific claims with `--oidc-required-claim=<claim>=<value>` Previously, there was no mechanism for a user to specify claims in the OIDC authentication process that were requid to be present in the ID Token with an expected value. This version now makes it possible to require claims support for the OIDC authentication. It allows users to pass in a `--oidc-required-claims` flag, and `key=value`...

to the kubelet that allows it to track container images and the list of authentication information that leads to their successful pulls. This data is persisted across reboots of the host and restarts of the kubelet.
  
  The kubelet ensures any image requiring credential verification is always pulled if authentication information from an image pull is not yet present, thus enforcing authentication / re-authentication. This means an image pull might be attempted even in cases where a pod...

- Increased `CSINodeIDMaxLength` from 128 bytes to 192 bytes. ([#98753](https://github.com/kubernetes/kubernetes/pull/98753), [@Jiawei0227](https://github.com/Jiawei0227))
- Kube-apiserver: The OIDC authenticator no longer waits 10 seconds before attempting to fetch the metadata required to verify tokens. ([#97693](https://github.com/kubernetes/kubernetes/pull/97693), [@enj](https://github.com/enj)) [SIG API Machinery and Auth]

- Adds metrics for the delegated authenticator used by extension APIs that delegate authentication logic to the Kube API server. ([#99364](https://github.com/kubernetes/kubernetes/pull/99364), [@p0lyn0mial](https://github.com/p0lyn0mial))

- Fix a data race in authentication between AuthenticatedGroupAdder and cached token authenticator. ([#109969](https://github.com/kubernetes/kubernetes/pull/109969), [@sttts](https://github.com/sttts)) [SIG API Machinery and Auth]