Merkelized Abstract Syntax Trees (MAST) is an improvement to the bitcoin protocol that will allow for more complex unlocking scripts on the bitcoin blockchain. Taproot is one codename for an upgrade that would add MAST.
While these scripts are available now, we are waiting for standardization of aggregate signature processes in order to improve the privacy characteristics and lower the transaction fees for our clients.
MAST would make complex unlocking scripts look identical and have identical size to simpler ones. This would allow us to add new layers of security for our users. For example, we could offer a 3-of-5 wallet that reverts to a single signature wallet after a few years have passed without spending from it. This would add a failsafe in inheritance scenarios where a user dies unexpectedly and some of their keys are unrecoverable. The single signature fallback could be controlled by the user’s estate executor.