ROASTing cheaper Fedimint Onchain Transactions
Fedimint is a federated ecash system designed for high availability and privacy. Federations hold Bitcoin that backs in mint in an onchain multisig and the federation uses a Byzantine Fault Tolerant consensus algorithm to come to consensus on the ordering of transactions within the system. Fedimint up until this point has used a P2WSH onchain multisig descriptor, but this does not scale well when the number of servers within the federation increases, because P2WSH requires a signature per signer. This talk will focus on how we upgraded Fedimint to use Taproot, FROST, and ROAST to collapse the required signatures to one, regardless of the federation size. This enables larger federations, without sacrificing on cost or onchain privacy. This talk will also demonstrate the cost savings and privacy benefits of upgrading Fedimint's signing mechanism to use ROAST.
