Description:    "Your key is too long",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrUnsignedHeaders: {
		Code:           "AccessDenied",
		Description:    "There were headers present in the request which were not signed",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidQueryParams: {
		Code:           "AuthorizationQueryParametersError",

### Signing Release Artifacts

Release artifacts are [signed](https://github.com/kubernetes/enhancements/issues/3031) using [cosign](https://github.com/sigstore/cosign)
signatures
and there is experimental support for [verifying image signatures](https://kubernetes.io/docs/tasks/administer-cluster/verify-signed-images/).

For detailed release notes on the three alpha features from SIG AWS, please refer to the following Changelogs:

- Kubeadm: add support for certificate chain validation. When using kubeadm in external CA mode, this allows an intermediate CA to be used to sign the certificates. The intermediate CA certificate must be appended to each signed certificate for this to work correctly. ([#97266](https://github.com/kubernetes/kubernetes/pull/97266), [@robbiemcmichael](https://github.com/robbiemcmichael)) [SIG Cluster Lifecycle]

   * signal the first active guard that is satisfied. But the corresponding thread may have already
   * been interrupted and is waiting to reacquire the lock while still registered in activeGuards,
   * in which case the signal is a no-op, and the bigger-picture signal is lost unless interrupted
   * threads take special action by participating in the signal-passing game.
   */

  /*

  - The requested name did not match the set of authorized names (`x509.HostnameError`)
  - The error surfaced after attempting a connection contained one of the substrings: "certificate is not trusted" or "certificate signed by unknown authority". ([#120736](https://github.com/kubernetes/kubernetes/pull/120736), [@MadhavJivrajani](https://github.com/MadhavJivrajani))

* 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))

		{serverType: "ErasureSD", signer: signerV4},
		// Init and run test on ErasureSD backend with signature v2.
		{serverType: "ErasureSD", signer: signerV2},
		// Init and run test on ErasureSD backend, with tls enabled.
		{serverType: "ErasureSD", signer: signerV4, secure: true},
		// Init and run test on Erasure backend.
		{serverType: "Erasure", signer: signerV4},
		// Init and run test on ErasureSet backend.

	if signature {
		if errCode := doesSignatureMatch(unsignedPayloadTrailer, req, globalSite.Region(), serviceS3); errCode != ErrNone {
			return nil, errCode
		}
	}
	if trailer {
		// Discard anything unsigned.
		req.Trailer = make(http.Header)
		trailers := req.Header.Values(awsTrailerHeader)
		for _, key := range trailers {
			req.Trailer.Add(key, "")
		}
	} else {
		req.Trailer = nil
	}

Now let's go back a bit and understand what is all that.

The `password` "flow" is one of the ways ("flows") defined in OAuth2, to handle security and authentication.

OAuth2 was designed so that the backend or API could be independent of the server that authenticates the user.

But in this case, the same **FastAPI** application will handle the API and the authentication.