This document presents Biscuit, a new multivariate Digital Signature Scheme (DSS) based on the hardness of solving a set of hard structured algebraic equations. Biscuit is in the lineage of the MQDSS and Picnic signature schemes that were submitted to the previous NIST post-quantum cryptography (PQC) standardization process . The high-level framework of Biscuit is similar to MQDSS and Picnic. It is derived from a Zero-Knowledge Proof-of-Knowledge (ZKPoK) using the Fiat-Shamir transform.