Hey #[1] I was talking with #[2] about how we could use one of your TapSigners in a USSD app and seems like the only way is to put your JavaCard chip into a SIM overlay packaging.. is that even possible?
Discussion
Hm.. nevermind, looks like even if a an overlay SIM siging chip could be put in a feature phone getting it to work with a USSD app isn’t going to work. Best bet for a non-custodial solution is probably future very budget smart phones with NFC.