Maybe, though that seems pretty fringe to me. I'd note that backing up the secret from a challenge/response token creates a big new class of attacks--it's much

Maybe, though that seems pretty fringe to me. I'd note that backing up the secret from a challenge/response token creates a big new class of attacks--it's much easier for someone to learn my secret without me realizing when that secret exists outside tamper-resistant memory. It would be better to register multiple different security tokens, or to program multiple security tokens identically and then destroy the key material afterwards (except for the copies inside the tokens).