A couple of questions about ARPA

[johnnynanjiang]

Hi Folks, a couple of questions about ARPA

1. Which blockchains does it support so far? e.g. does it support blockchains that use ECDSA?

2. How does the threshold signature scheme work in a permissionless network? e.g. if there are 10 nodes, how to manage nodes joining and leaving and still make TSS work?

Thanks and regards,