On Wed, May 23, 2018 at 09:05:15AM +0800, Craig Ringer wrote:
> Presumably it'd have to support some non-equality ops like < and > for b-tree
> indexing, so you can compare two encrypted texts without decryption.
>
> If the user can supply cleartext to be compared against, this exposes
> search-based plaintext attacks where you can discover the plaintext over time
> with iterative searches over modified plaintext.
>
> My understanding of homomorphic encryption is that it's generally more useful
> for data-modifying operations. For example, you might want to add a value to a
> balance without being able to read the balance and learn the current value. I
> haven't heard of it being used for searches before.
I have a slide about indexing encrypted data; not sure if it is
relevant:
https://momjian.us/main/writings/crypto_hw_use.pdf#page=86
--
Bruce Momjian <br...@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
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