Add invariant noise to decryptor #545
Open
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
rickwebiii
commented
Aug 9, 2022
| for (size_t i = 0; i < coeff_modulus_size; i++) { | ||
| auto power = static_cast<double>(sizeof(uint64_t) * 8 * i); | ||
| auto word = static_cast<double>(norm.get()[i]); | ||
| invariant_noise += word * exp2(power); |
There was a problem hiding this comment.
Looking through other code, I suspect this is the wrong way to reduce a coefficient into a double precision number as this doesn't take into account the coefficient modulus values.
There was a problem hiding this comment.
Nevermind, I now think this is correct. The coefficients are indeed stored as RNS, which is what led to my doubt. However, invariant_noise_internal (the code I factored out of the existing invariant_noise_budget function) calls compose_array(noise_poly, coeff_count, pool_) before computing the infinity norm. This converts the RNS to multi-precision, so the infinity norm is a multi-precision value, which is what I was assuming here.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Allow users to read the invariant noise as a double precision value. This provides more fidelity when validating noise models.