I was wondering if it's currently possible to verify personal or private information on-chain on Ethereum. Specifically, I would like it to be verifiable that a certain amount of an ETF is held on a platform such as Trading 212 or Etoro.

But other examples which would have similar functionality to what I'm looking for are:

  • verifying the amount of off-chain reserves held by a stablecoin
  • verifying your credit score on Expedia
  • verifying you are the holder of tickets to a concert etc.

Please let me know if there are any tutorials or code to look at that has this functionality that I'm looking for (being able to verify non-public data securely on chain). Alternatively, if this isn't possible using Ethereum that would also be great to know. I'm aware that oracles can be used to access specific public data on chain. However, I was wondering if the same access for private data is being worked, maybe using zero knowledge. I guess this may be impossible considering login access would need to be available on chain for miner to verify. Maybe there is some layer 2 solution?

1 Answer 1


Quham Adefila

Take a look in [Chainlink Proof of Reserve] (https://docs.chain.link/data-feeds/proof-of-reserve)

If you can not find the source over there, you can have your own source and use Chainlink Functions to get the information

  • Thank you. This is one of the options I was considering but since the data is private no Oracle would already have access. And if I were to make my own oracle I would be the only one with access and hence I would need to be trusted to provide the accurate data. Unfortunately, I doubt there is currently a way to provide private data trustlessly e.g. some cryptographic signature ensuring data is untampered but I thought I would ask anyway. Commented Feb 20 at 22:08

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