Agenda Request - Malicious Partitioning Without Sorting

[schoppmp]

Agenda+: What do you want to discuss?

I would like to present a protocol that aims to solve partitioning / sharding for IPA. This is related to several issues in the IPA repository (see links below).

A draft can be found here. The high-level idea is to have the three servers repeatedly add "dummy" ciphertexts together with local shuffling and ciphertext rerandomization.

There a two variants of our protocol: One maps the inputs to a small pseudorandom domain of size equal to the number of shards. The advantage here is that only very few dummy contributions are needed. The second one allows for a large pseudorandom domain. We think this one is of particular interest to IPA, since it would allow aligning events with the same match key in the clear, thus reducing the amount of sorting that needs to be done in MPC in each partition.

Time

20 minutes presentation, 25 minutes discussion

Links

Protocols to be discussed: https://docs.google.com/document/d/1-CUBMH3YCXnn0c6EDeBQ31Fw9T1ESYVgbYlyK4MelBY/edit?resourcekey=0-zwgbY2pJ06Sp4D_viQp02g
Related issues: patcg-individual-drafts/ipa#35, patcg-individual-drafts/ipa#49, and patcg-individual-drafts/ipa#75

[schoppmp]

If possible I'd prefer a slot on Thursday or Wednesday later in the afternoon.

[schoppmp]

Slides from today: https://docs.google.com/presentation/d/1cQC8rcqHHK61mLs8wZTmgRF3ckpe5fFENgpNk16VqrQ/edit?usp=sharing