Bitcoin Core has taken a significant step forward in implementing Schnorr signatures by merging BIP340 support into the libsecp256k1 library. The update introduces an experimental module named “schnorrsig” that implements the signing and verification of Schnorr signatures as well as test vectors and a benchmarking tool.
Although this does not mean that the use of Schnorr is currently live on the Bitcoin network, it does represent a significant step forward. “With this merged, the pull request that adds taproot to Bitcoin Core can be taken much more seriously,” Bitcoin developer Ben Carman of Suredbits shared with the BTC Times.
The pull request was first opened by Blockstream's Jonas Nick in September of 2018 and merged after two years of intense review. Those who participated in its testing include notable Bitcoin Core contributors such as Andrew Poelstra, Gregory Maxwell, Pieter Wuille, Ben Carmen, Max Hillebrand, John Newberry, Russell O’Conner, and Tim Ruffing.
The next steps for Schnorr involve creating a separate pull request in order for Bitcoin Core to use the latest version of the libsecp256k1 library. This will allow the reference client to call on the newest version of the library to sign and verify Schnorr based signatures and will make reviewing the current version of the Taproot pull request significantly easier. This proposal is expected to be merged fairly quickly as the last update of the library took only 3 days.