Visual Overview of Schnorr Signatures for Bitcoin

March 19, 2019

Bitcoin is a fascinating work of art; continuous improvements are at first discussed and then if consensus arises, implemented by the extended community. Within our research into the Bitcoin protocol, we've strengthened our belief in privacy as a right and we believe it should eventually be implemented by default in the Bitcoin protocol. We see it at as a must, considering the increasing types of attacks that can be used against a user's privacy and a need to preserve UTXO's fungibility.

One of the most interesting potential improvements in Bitcoin are the Schnorr signatures. Since the inception of Bitcoin, this cryptographic scheme has been discussed as a potential alternative to ECDSA (Elliptic curve digital signature algorithm) for better authentication of signatures. However, it remained theorical mostly because the patent on Schnorr signature expired in 2008 and little pratical work had been done with this technology.

Recent work by Blockstream has lead to a concrete implementation of Schnorr signatures called MuSig, which is compliant to the corresponding BIP for Schnorr signatures, written by Peter Wuille. Heavy testing and reviewing will be necessary before it gets implemented into Bitcoin Core. There is a long way ahead but it is a start.

While this upcoming improvement would also come in hand into a single softfork with other technologies such as MAST and Taproot, a big part of the community still doesn’t understand what exactly it is and which problems it solves. Following a (funny) discussion with Max Hillbrand (@HillebrandMax) and Pieter Wuille (@pwuille) on twitter about this, we realized that information about Schnorr Signatures tends to be scattered and not vulgarized.

In response, we created this easy to follow visual framework about the current signature authentication scheme (ECDSA) in Bitcoin, and how Schnorr Signatures will improve it in terms of scalability, privacy, computational costs and security. Don't hesitate to contact us if you have any questions and feel free to share it. Enjoy!