FROST

TL;DR

FROST (Flexible Round-Optimized Schnorr Threshold Signatures) is a cryptographic protocol used to securely create digital signatures with multiple parties, while keeping it efficient and private.

Botanix Labs leverages the FROST protocol to secure the decentralized multisigs that constitute the Spiderchain. Using FROST, we will be able to have larger multisigs in the future.

The basic design principle of the Spiderchain is bigger decentralized multisig sizes in order to mathematically secure the bitcoin. On Bitcoin, multisig sets with a large number of signatories will cause users exorbitant fees. FROST: Flexible Round-Optimized Schnorr Threshold Signatures introduces fee savings by aggregating the public keys and signatures to reduce the on-chain footprint.

FROST (Flexible Round-Optimized Schnorr Threshold Signatures) is a protocol that minimizes the number of rounds of communication between participants in Schnorr signature schemes, reducing network bandwidth, time, and probability of errors. It requires a maximum of three rounds for signing, even without a trusted signature aggregator or preprocessing stage. It can be used to implement 'n-of-m' threshold signatures represented by a single signature on the blockchain. This saves block space and increases privacy by making them indistinguishable from other, more common spend types.

More information on FROST can be found by reading its official whitepaper and watching the visual explainer below, provided by Blockstream.

Size of the multisig

There is a tradeoff on the size of the multisigs. One could imagine one single multisig of 1000 participants. The signing of these 1000 signatures will take a non- trivial amount of time, and possible coordination issues could arise. Moreover, if malicious actors gain control of a 2/3rd majority, they immediately have access to the full amount of capital locked in the Spiderchain. By splitting the collateral into multiple smaller multisigs, the capital at risk is lowered. However, if the multisig size is too small, security to protect against malicious adversaries can be lost and accidental crashes or key losses can lead to lost bitcoin.

FROST notebook

For a technical explanation of FROST please refer to: https://github.com/0xBEEFCAF3/FROST-Notebook/blob/main/README.md