really self-soverign Id

 forget about id cards or apps on secure mobile devices - the future is here and it is simple and secure.

We splice octopus DNA into humans so that we are all equipped with chromatophores on our faces and hands - we learn from an early age (like Octopi) to control these, and can use them to display a wide variety of images, including QR codes that reveal (for example) age verification data, or, more handily, video sent over the net to us (so our phone no longer needs a display), e.g. on our palms.

data minimisation, no power source/charing necessary, no Id theft possible. 

game over. sustainably.

hey, also useful for people to communicate who have (like me) challenged hearing or speech.