Declassify the random seed #39
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fdupress
reviewed
Jun 14, 2024
This changes what is declassified and when. Before, declassification only occurs during rejection sampling and what is declassified is whether rejection occurs or not. After, the full sampling of the matrix expects its seed to be public: what is declassified is the public key when it is read from memory in the IND-CPA encryption, when it is derived from the output of SHA3 in keygen.
fdupress
approved these changes
Jun 17, 2024
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Good to go.
There are arguments (see also on Zulip, made by me after I thought some more) that we may want to declassify the public output of keygen instead of having an internal declassification which is harder to justify purely from the security model. But we can do this as a second go once we settle the discussions.
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This changes what is declassified and when.
Before, declassification only occurs during rejection sampling and what is declassified is whether rejection occurs or not.
The full sampling of the matrix expects its seed to be public: what is
declassified is the public key when it is read from memory in the
IND-CPA encryption, and the public seed when it is produced by a call
to SHA3 in keygen.