Nullifier
ZK Compression · Abyss
A cryptographic value derived deterministically from a compressed account's leaf hash, published on-chain when the account is consumed to permanently mark it as spent and prevent double-spending. In Light Protocol, nullifiers are inserted into an on-chain queue and batch-processed by Forester nodes into a Merkle tree, allowing validity proofs to assert both account existence (inclusion proof) and that the nullifier has not been recorded (non-membership proof). This scheme treats compressed accounts as UTXOs — each consumed once and replaced by new output accounts.