code: func loadPublicKey(bs []byte) (*ecdsa.PublicKey, error) {
  	// Decode and parse the public key PEM block
  	block, _ := pem.Decode(bs)
  	if block == nil || block.Bytes == nil {
  		return nil, errors.New("unsupported public key format")
  	}
  	intf, err := x509.ParsePKIXPublicKey(block.Bytes)
  	if err != nil {
  		return nil, err
  	}
  
  	// It should be an ECDSA public key
  	pk, ok := intf.(*ecdsa.PublicKey)
  	if !ok {
  		return nil, errors.New("unsupported public key format")
  	}
  
  	return pk, nil
  }
docs: // loadPublicKey returns the ECDSA public key structure for the given PEM
  // data.