code: func ParsePublicKeyDER(der []byte) (crypto.PublicKey, error) {
  	generalKey, err := x509.ParsePKIXPublicKey(der)
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return generalKey, nil
  }
docs: // ParsePublicKeyDER parses unencrypted DER-encoded publice key