FASTER, AGGREGATABLE, AND QUANTUM SAFE PRIVACY POOLS

Summary from the TLDR Crypto newsletter

A new ethresear.ch proposal ports Tornado Cash-style privacy pools to Flock, a transparent hash-based SNARK using SHA-256 for the Merkle tree and nullifier derivation, removing the discrete-log assumptions in Pedersen commitments and Groth16. A stepwise circuit that runs one SHA-256 compression 34 times with a sumcheck glue argument cuts prover time 28x, from 810ms to 28.6ms at depth 32, with a 266 KiB proof size. An aggregation layer lets users prove withdrawals locally in ~19.5ms each, then folds N proofs into a single ~344 KiB proof that verifies in 46-64ms regardless of batch size. The scheme also includes a ZIP 2005-inspired quantum recovery protocol: if a cryptographically relevant quantum computer is announced, the pool freezes, and users withdraw through a post-quantum recovery verifier seeded from their original 256-bit key, leaving nullifier tracking intact.