[curves] Threshold ECDSA for Bitcoin

[Trevor Perrin]

https://freedom-to-tinker.com/blog/stevenag/new-research-better-wallet-security-for-bitcoin/
http://www.cs.princeton.edu/~stevenag/bitcoin_threshold_signatures.pdf

Apparently based on this:

http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.67.9913

I'd be interested to hear how the state-of-the-art in threshold-ECDSA
compares to threshold-Schnorr, if anyone knows.


Trevor