Is there a reference to CKKS proxy re-encryption used in openFHE?

FHE Questions
1

Hello，
I read the OpenFHE : Open-Source Fully Homomorphic Encryption Library, which introduces the proxy re-encryption of CKKS is a little brief, and its reference is only the proxy re-encryption of BV and NRTU, as if there is no CKKS proxy re-encryption. Can you provide a detailed introduction ? I want to know the specific details of CKKS proxy re-encryption to complete my thesis.

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2

We are planning to post a paper on PRE algorithms in OpenFHE a little bit later (in Q1 2024).

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3

hello. how can i access the paper about CKKS PRE?

4

We haven’t posted it yet (got side-tracked with other projects).The current ETA is May.

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5

The PRE paper is now posted at HRA-Secure Homomorphic Lattice-Based Proxy Re-Encryption with Tight Security Note that it describes in detail the instantiation for BGV, but the extensions to CKKS and BFV are relatively straightforward.

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6

I did run PRE, making the suggested changes by you in the other post on PRE. May I know, what re-encryption key generation algorithm is used in the case of CKKS PRE?

The reason I want to know this is,

  1. Is there any risk of making the reencryption key public?

Thanks very much.

7

For CKKS, only the IND-CPA and FIXED_NOISE_HRA are supported. Achieving NOISE_FLOODING_HRA is harder because it would significantly increase the scaling factor.

The re-encryption key should not be made available to the party that knows the new secret key as this party can decrypt the message to find the prior secret key.