This blog is inspired from a brilliant research work by Dan Boneh, Manu Drijvers and Gregory Neven. The trio have constructed new multi-signature schemes that provide new functionality with an aim to reduce the size of the Bitcoin blockhain. This construction are in the plain public key model, meaning that users do not need to prove knowledge or possession of their secret key.
Multi-signature scheme is a protocol that enables the n signers who want to sign the same message m to jointly generate a short signature σ on m, this σ will convince a verifier that all n parties have signed m.
The multi-signature σ should be short; its length should be independent of the number of signers n. We define this concept more precisely in the next section, where we also present the standard security model for such schemes. Secure multi-signatures have been constructed from Schnorr signatures, from BLS signatures and from many other schemes. A more general concept called an aggregate signature scheme lets each of the n parties sign a different message, but all these signatures can be aggregated into a single short signature σ. As before, this short signature should convince the verifier that all signers signed their designated message.
Application of multi-signature concept for Bitcoin blockchain
Mutlisig address is defined as the hash of n public leys along with some number. In recent work, Maxwell, Poelstra, Seurin, and Wuille suggest using multi-signatures to shrink the transaction data associated with Bitcoin Multisig addresses. By using Multisig, all n signatures can be compressed into a single short signature. This shrinks the overall transaction sice and reduces the amount of data written to the blockchain. This implies that Multisig protocol shrinks the amount of data written to the blockchain by a factor of n.
If you are interested to read more, then click on this link: https://eprint.iacr.org/2018/483.pdf
