SMPC is a subfield of cryptography that allows parties to compute a function while keeping the inputs private.
Secure multi-party computation (sMPC) is a part of cryptographic that allows a computation to be distributed across multiple different parties, and no one party can see the other parties’ data — it is kept private.
In blockchain, this means that nodes can jointly compute a function while keeping the inputs private from everyone, including the nodes that power them. SMPC also means that analysts are able to securely and privately compute distributed data without ever exposing it publicly.