The web wallet’s Cardano account: standard CIP-1852 HD keys from the
recovery phrase, so the same phrase restores the same account in Lace,
Eternl or Yoroi.
Lovejoin’s proofs, on BLS12-381 G1: the Schnorr proof a box’s owner gives
to withdraw it, and the N-way sigma-OR proof a mix gives for each box it
re-randomizes. A port of Lovejoin’s TypeScript prover
(offchain/src/crypto/, MIT) onto blstrs, checked against its known-answer
vectors byte for byte, so the deployed validators accept what it proves.