Blockstream dreams up a whole new type of multisig called ROAST

Blockstream, a Bitcoin-focused blockchain tech company, has published a proposal to create a new multisig standard called Robust Asynchronous Schnorr Threshold Signatures.

It aims to prevent transaction failures caused by absent or malicious signers, and can be scaled.

Multisignature or multisignature is a term that refers to transactions in which multiple signatures must be signed off before the transaction can be executed. This standard is widely used in crypto.

Blockstream research’s May 25 blog post explains that ROAST’s basic purpose is to make transactions between Blockstream and the Bitcoin network more efficient, private, and automated.

Particularly, ROAST was positioned as a signature standard which could be used with and improve threshold signature schemes like FROST (Flexible round-optimized Schnorr Threshold Signatures):

ROAST wraps threshold signature schemes such as FROST. It ensures that there is a quorum (e.g. the Liquid functionaries) who can obtain valid signatures even when disruptive signers are present.

Researchers found that FROST is an efficient method to sign off on BTC transactions. However, the structure of signers and coordinators in FROST makes it less secure than “automated signature software”.

Researchers claim that ROAST can provide sufficient reliable signers for each transaction to solve the problem. It can also be used at a larger scale than the Blockstream 11-of-15 multisig standard.

“Our empirical performance evaluation has shown that ROAST scales well with large signer groups. e.g., an 67-of 100 setup with the coordinator, and signers from different continents,” reads the post.

“Even with 33 malicious signatures that try to block signing attempts, (e.g. “Even with 33 malicious signers that try to block signing attempts (e.g., by sending indecent responses or not responding at all), the 67 honest signatures can produce a signed document within a matter of seconds.”

The ROAST team explained ROAST’s operation by using an analogy of a democratic council that is responsible for the legislation of “Frostland”.

The argument is that it can be difficult to get Frostland legislation (transactions), signed off because of a multitude of factors at any one time. This can lead to the majority of councilmembers suddenly becoming unavailable or absent.

To counteract this, a council secretary must compile and maintain an adequate list of signers (supporting council members) at all times, so there are always enough members to pass legislation.

“If at most seven council members support the bill and act honestly, then he knows that at any moment these seven members will sign their current assigned copy and be re-added on the secretary’s lists.”

The post states that the secretary can be certain that seven of his members will appear on his list at some point in time, so the signing process will not be stuck.

Related: Former Blockstream executive says that ‘DeFi’ is not decentralized.

ROAST is part of a collaboration among Blockstream researchers Tim Ruffing, Elliott Jin, Viktoria Roge and Dominique Schroder (University of Erlangen-Nuremberg) and Jonas Schneider–Bensch (CISPA Helmholtz Center for Information Security).

The researchers linked to a 13-page research paper that provides a more detailed overview of ROAST.

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Eileen Wilson

Eileen Wilson –Technology and Energy My Name is Eileen Wilson with more than 5 years of experience in the Stock market industry, I am energetic about Technology news, started my career as an author then, later climbing my way up towards success into senior positions. I can consider myself as the backbone behind the success and growth of with a dream to expand the reach out of the industry on a global scale. I am also a contributor and an editor of the Technology and Energy category. I experienced a critical analysis of companies and extracted the most noteworthy information for our vibrant investor network.

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