search

monero-project / research-lab

A general repo for Monero Research Lab work in progress and completed work
238 stars 77 forks source link

Proof data storage #64

Open SarangNoether opened 4 years ago

SarangNoether commented 4 years ago

It's possible to storage data in a Bulletproof range proof, under particular trust assumptions. In particular, knowledge of a PRNG seed used for random element generation can be used to store 32 bytes of arbitrary data; however, this allows for the brute-force recovery of all Pedersen values used in the proof by any entity that knows the seed. For a proof consisting of exactly one Pedersen commitment, the inclusion of another 32 bytes of data is possible, but this leaks the Pedersen mask. Storage of data should therefore be intended only for use by the prover.

Similarly, it's possible in Triptych to store 64 bytes of arbitrary data per proof in a way that leaks the signing index to a PRNG seed holder.

boogerlad commented 3 years ago

Is storing 64 bytes of arbitrary data still possible with Triptych? If so, couldn't this be used to replace tx_extra?

SarangNoether commented 3 years ago

Yes, a Triptych proof can store 64 bytes of arbitrary data using a seeded PRNG.

boogerlad commented 3 years ago

Is this a "bug" or a "feature"? That is, will the ability to store arbitrary data eventually be removed? I can think of some pretty nifty use cases.

SarangNoether commented 3 years ago

The network can't detect it, so it's not possible to "remove" this feature. It's entirely up to client software to embed and/or recover this data.

UkoeHB commented 1 year ago

Here is a paper about inserting a communication channel via steganography: https://ieeexplore.ieee.org/abstract/document/9356584