SHA3-512 commitment + nullifier opening. The node sees the trapdoor. claim=opening_not_zk. Not Groth16, Bulletproofs, or ZK-Shield. privacy_mint_zk is an ML-DSA wrap, not a circuit — this page does not call it. Mint/spend need ADDITION_PRIVACY_MASTER_KEY (≥32 chars) on the daemon. Without it the node returns error: ADDITION_PRIVACY_MASTER_KEY not set or too short (min 32).