Circom

About

Circom is a circuit compiler developed and maintained by the iden3 team that lets developers define arithmetic circuits as templates and compile them to R1CS constraint systems. It is one of the most widely used ZK circuit languages, powering projects such as Tornado Cash, Semaphore, and Dark Forest. From a security perspective, circom's low-level constraint model makes under-constrained signals a common and dangerous bug class, which is why dedicated analyzers like Circomspect and Picus target it. Circuits compiled with circom are typically proven with snarkjs or rapidsnark using Groth16 or PLONK.