func moveKeysWithNewPassphrase(oldKeyStore, newKeyStore *trustmanager.KeyFileStore, outputPassphrase string) error {
	// List all files but no symlinks
	for _, f := range oldKeyStore.ListFiles(false) {
		fullKeyPath := strings.TrimSpace(strings.TrimSuffix(f, filepath.Ext(f)))
		relKeyPath := strings.TrimPrefix(fullKeyPath, oldKeyStore.BaseDir())
		relKeyPath = strings.TrimPrefix(relKeyPath, string(filepath.Separator))

		pemBytes, err := oldKeyStore.Get(relKeyPath)
		if err != nil {
			return err
		}

		block, _ := pem.Decode(pemBytes)
		if block == nil {
			return ErrNoValidPrivateKey
		}

		if !x509.IsEncryptedPEMBlock(block) {
			// Key is not encrypted. Parse it, and add it
			// to the temporary store as an encrypted key.
			privKey, err := trustmanager.ParsePEMPrivateKey(pemBytes, "")
			if err != nil {
				return err
			}
			err = newKeyStore.AddEncryptedKey(relKeyPath, privKey, outputPassphrase)
		} else {
			// Encrypted key - pass it through without
			// decrypting
			err = newKeyStore.Add(relKeyPath, pemBytes)
		}

		if err != nil {
			return err
		}
	}

	return nil
}