Whizz-bang cryptographic solutions to this class of problem (digital ID, electronic voting, etc) have at least three major problems that I consider fatal:
1. The contract to build the thing will go to the lowest bidder, who is all but guaranteed not to do any of it correctly (cf. the UK Post Office scandal and Fujitsu's role in it).
2. The public has no guarantee that it is implemented in the cryptographically secure way, or that is is ONLY implemented in the cryptographically secure way (e.g., either by accident or through malice the system leaks info it shouldn't).
3. The overwhelming majority of the public are not trained in nearly enough computer science to understand "no actually this system isn't a total privacy nightmare" (assuming that it's actually implemented securely).
1. The contract to build the thing will go to the lowest bidder, who is all but guaranteed not to do any of it correctly (cf. the UK Post Office scandal and Fujitsu's role in it).
2. The public has no guarantee that it is implemented in the cryptographically secure way, or that is is ONLY implemented in the cryptographically secure way (e.g., either by accident or through malice the system leaks info it shouldn't).
3. The overwhelming majority of the public are not trained in nearly enough computer science to understand "no actually this system isn't a total privacy nightmare" (assuming that it's actually implemented securely).