Quote from: Crowex on March 10, 2015, 02:58:11 PM

Quote from: luv2drnkbr on March 09, 2015, 07:44:42 PM

I read the paper on threshold signatures and I thought it would be a fun project -- and immense challenge, since I'm not an expert programmer or cryptographer! -- to try to write a Python module to implement it.

However, one aspect required is deriving shares of a random number (the K value, and also the initial private key) without ever having or revealing the fully constructed value. They mention this is possible but don't show the protocol for it.

Instead, they reference the paper "A robust threshold elliptic curve digital signature providing a new verifiable secret sharing scheme" by the authors M.H. Ibrahim, I. Ali, I. Ibrahim, and A. El-sawi. This paper supposedly includes the protocol for JRSS

I cannot find a copy of that paper online, and I was hoping somebody else might be able to find it, or already have it, or simply know the protocol for generating shares of a random value without anybody knowing the random value (aka JRSS).

I could be misunderstanding it but I don't think you can actually use the JRSS method for a t-of-n threshold scheme as described in their paper. I'm not sure what dealer-less method you can use. I've asked a question on their blog so maybe they'll clarify.

EDIT I've looked a it a bit more and I think I probably was mis-understanding it

The JRSS isn't for the signature itself, it's for deriving dealer-less shares of a random k value among the t-of-n participants without revealing k. (And can also be used to create shares of a new random private key without a dealer and hence without anybody ever knowing the private key.)