Fair Data Exchange at Near-Plaintext Efficiency

The Fair Data Exchange (FDE) protocol (CCS '24) provides atomic pay-per-file transfers with constant-size proofs, yet existing implementations remain unscalably slow (about 1 second per 4 KiB) and inflate ciphertexts by 10--50x. We introduce an FDE implementation that achieves near-plaintext speeds and sizes, making fair exchange practical even for gigabyte-scale files.