Schnorr signatures will incorporate improvements regarding network privacy. The information was shared with the community of developers in New York and San Francisco.
Developer John Newbery explains why Schnorr and Taproot are useful mechanisms that can be combined although both are still in development. The Bitcoin Core collaborator highlights the properties of Schnorr signatures, which will incorporate improvements regarding network privacy.
Scalability is another benefit that Newbery attributes to the Schnorr and Taproot proposal, which, due to its linearity properties, allows improvements in batch validation by blocks 2.5 times faster.
The engineer is pleased with the privacy offered by this new protocol since he considers it important to express a multi-signature configuration as a single key and signature, so that the expenditure policy is not leaked to the chain.
Newbery explains that it is possible to use data to configure a private key and a public key. He also highlights that the Schnorr and Taproot proposals have expenditure paths that remain hidden unless they are actually executed.
The Taproot proposal, first made in 2018 by Bitcoin Core collaborator and former Blockstream CTO, Gregory Maxwell, would expand on the flexibility of the Bitcoin smart contract on the network, allowing greater privacy.
Maxwell believes that Schnorr signatures are superior to the Elliptic Curve Digital Signature Algorithm (ECDSA), since they are 11% smaller. They are compatible with existing private keys and have the same level of security, but the verification algorithm is linear, which explains why it allows new functionalities.
Schnorr allows the aggregation of keys and signatures, for the possibility of using MuSig to aggregate and maintain an additionally aggregated key. It is also possible to define multiple cryptocurrency expenditure conditions, such as having a primary expenditure script and an alternative expenditure script.
Schnorr and MuSig Signatures
Schnorr signatures produce a smaller chain size, support faster validation and have a better privacy. They natively allow combining multiple signatures into one, through aggregation. They also allow complex expenditure policies.
MuSig is a multiple signature schemes, that is, a combination of a signature and verification algorithm in which multiple signers, with their respective private or public keys, jointly sign a single message, resulting in a combined signature. This can be verified by anyone who knows the message and the public keys of the signers, for which a reliable configuration is required.
Taproot
Developer James Chiang explains the advancements of Taproot as a component, such as allowing the user to have a predetermined expenditure path, that is, spend a public key. With Schnorr signatures, it is possible to have a single key and a single signature, or multiple signatures that cannot be distinguished in the chain. There is also the ability to use the same output through alternative expenditure paths, which are loaded with a bitcoin script called tapscript.
Taproot would allow almost any construction of Smart contracts to include a condition so that all participants would match a result. Participants can cooperate and sign a settlement transaction together, which would lead to space savings and an increase in the privacy of scripts.
In addition, Chiang shows how to create SegWit v1 transaction outputs and use them with the key expenditure route, considering that an innovation like Taproot is possible thanks to Segregated Witness (SegWit), which introduced the creation of script versions, an extension of the Bitcoin protocol that allows implementing new cryptographic signature algorithms in the Bitcoin network.
By Willmen Blanco
