Comment by mike_hearn

Riffing off the identity thing, one service I wanted for a while is something that issues X.509 certificates based on verified phone numbers. Phone numbers are a pretty great identity, perhaps the most successful private sector identity system ever, but they're expensive and annoying to verify, and the verification isn't portable across systems. A CA that did SMS verification and then gave you a certificate you could use with S/MIME or bind to passkeys or just use to sign software/documents in general, would democratize stable cryptographic identity. People generally can't handle key management directly, it's too easy to lose keys, but issuing transient keys tied to a phone number is much more palatable.

And PNs have got good features you want in general:

• Can have >1 of them if you want.

• Anonymous if you want.

• Not tied to any specific provider due to number portability laws.

• Hard to lose; phone companies will accept govt issued ID to get your account back if you lose your SIM and it's tied to a contract.

• Verifiable over the internet.

The only problem with them is they don't yield asymmetric keypairs.

The difficulty is business model. The people who want to consume such certificates are people who don't want to pay to verify numbers directly, but users don't want to pay either. So who pays.