I'm not an expert in the field, but there certainly have been efforts here and there to make "lightweight" crypto that needs little computational resources (and

I'm not an expert in the field, but there certainly have been efforts here and there to make "lightweight" crypto that needs little computational resources (and therefore battery power). One example would be KASUMI[0]. [0]: https://en.wikipedia.org/wiki/KASUMI https://en.wikipedia.org/wiki/KASUMI