key name "%s" must start with lowercase alphanumeric charact

Error message

key name "%s" must start with lowercase alphanumeric characters and can include "-" or "_" after the first character

What it means

Error "key name "%s" must start with lowercase alphanumeric characters and can include "-" or "_" after the first character" thrown in docker/cli.

Source

Thrown at cmd/docker-trust/trust/key_load.go:49

	var options keyLoadOptions
	cmd := &cobra.Command{
		Use:   "load [OPTIONS] KEYFILE",
		Short: "Load a private key file for signing",
		Args:  cli.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			return loadPrivKey(dockerCLI, args[0], options)
		},
		DisableFlagsInUseLine: true,
	}
	flags := cmd.Flags()
	flags.StringVar(&options.keyName, "name", "signer", "Name for the loaded key")
	return cmd
}

func loadPrivKey(streams command.Streams, keyPath string, options keyLoadOptions) error {
	// validate the key name if provided
	if options.keyName != "" && !validKeyName(options.keyName) {
		return fmt.Errorf("key name \"%s\" must start with lowercase alphanumeric characters and can include \"-\" or \"_\" after the first character", options.keyName)
	}
	trustDir := trust.GetTrustDirectory()
	keyFileStore, err := storage.NewPrivateKeyFileStorage(trustDir, notary.KeyExtension)
	if err != nil {
		return err
	}
	privKeyImporters := []trustmanager.Importer{keyFileStore}

	_, _ = fmt.Fprintf(streams.Out(), "Loading key from \"%s\"...\n", keyPath)

	// Always use a fresh passphrase retriever for each import
	passRet := trust.GetPassphraseRetriever(streams.In(), streams.Out())
	keyBytes, err := getPrivKeyBytesFromPath(keyPath)
	if err != nil {
		return fmt.Errorf("refusing to load key from %s: %w", keyPath, err)
	}
	if err := loadPrivKeyBytesToStore(keyBytes, privKeyImporters, keyPath, options.keyName, passRet); err != nil {
		return fmt.Errorf("error importing key from %s: %w", keyPath, err)

View on GitHub (pinned to e9452d6e78)

When it happens

Trigger: Thrown at cmd/docker-trust/trust/key_load.go:49 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of docker/cli@e9452d6e78 (2026-08-01). Data as JSON: /data/errors/9c9625e822cd90ea.json. Report an issue: GitHub.