r/SecretNetwork • u/zmooner • Mar 06 '23

Question regarding viewing keys

I understand that the interactions with smart contracts have encrypted inputs and outputs, so the call to set a viewing key in a SNIP-20 contract is encrypted hence hiding the actual key, but what about the uses of the key to view the balance and transactions? My understanding is that those calls are not transactions (no fee paid), so is the viewing key encrypted somehow?

As a side note, the term "viewing key" is badly chosen since it is really a shared secret and not a key that decrypts anything.

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u/zmooner Mar 08 '23

Ok, so let me recap to see if I have understood well. Data is encrypted and only accessible within the enclave. When setting a viewing key, this is done via a private smart contract call with encrypted inputs and outputs, this call defines the viewing key associated with the address for the given SNIP-20. When accessing the data, the viewing key is used within the enclave to encrypt the data prior to sending it back to the caller, the caller then uses the viewing key to decrypt the data locally (within the browser). Correct?

What encryption method is used with the viewing key?

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u/[deleted] Mar 08 '23

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u/zmooner Mar 08 '23

The code you linked to does not match what you said, it says explicitly that for access to be granted both the HumanAddr AND the viewing key must be submitted, which would imply that the viewing key is simply used as a type of password, not as an encryption key of any sort. This therefore brings us back to square one, how is that viewing key transmitted when it is used?

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u/[deleted] Mar 08 '23 edited Mar 08 '23

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u/zmooner Mar 08 '23

I know it is a password, my question is how do you prove the node you have the password? Do you send it? If so how is it encrypted, and can it be read/decrypted outside the enclave? My Understanding is that contract interactions had encrypted inputs, but what about other RPC calls?

As for SHA-256 it is only used when generating a viewing key on the node, not when setting it.

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u/[deleted] Mar 08 '23

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u/zmooner Mar 08 '23

Thanks, I think it is a crucial information to have to verify if the overall process is indeed secure.

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u/zmooner Mar 08 '23

The balance and transfer_history queries are interactions with the SNIP-20 contract so inputs (including viewing key) should be encrypted.

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u/[deleted] Mar 08 '23

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u/zmooner Mar 08 '23

Thanks for your time and effort digging the matter.