30 lines
1.7 KiB
Markdown
30 lines
1.7 KiB
Markdown
# Multiparty & 3-server {#multiparty}
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Two-party keys are the default. The library also builds three-evaluator
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`(2,3)` keys, information-theoretic three-server DPFs, and dealer-free
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two-party keygen when the index is already shared.
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| Construction | Parties | Header |
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| --- | --- | --- |
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| [dpf::make_dpf3](@ref dpf/dpf3.hpp) | Any two of three open (Shamir / dual spine, [ePrint 2024/1658](@ref bib_dpf3)) | `dpf3.hpp` |
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| [dpf::make_dpf3_doerner_shelat](@ref dpf/dpf3_ds.hpp) | Same keys from XOR shares of `alpha` | `dpf3_ds.hpp` |
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| `make_dpf3_cmp` / `make_dpf3_ic` / `make_multipoint3` | Comparisons, intervals, multipoint | `dpf3_cmp.hpp`, `dpf3_multipoint.hpp` |
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| [dpf::make_it_dpf3](@ref dpf/it_dpf3.hpp) | Information-theoretic 3-server DPF ([ePrint 2023/028](@ref bib_itdpf)) | `it_dpf3.hpp` |
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| [dpf::make_dpf_doerner_shelat](@ref dpf/doerner_shelat.hpp) | Two parties, shared index, no dealer for the point | `doerner_shelat.hpp` |
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| [dpf::geneval_*](@ref dpf/geneval.hpp) | Answer shares for one query, no reusable key | `geneval.hpp` |
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```cpp
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auto [k1, k2, k3] = dpf::make_dpf3(std::uint8_t{42}, dpf::fp61{7});
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auto opened = dpf::reconstruct(
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dpf::as_share(k1, dpf::eval_point(k1, std::uint8_t{42})),
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dpf::as_share(k2, dpf::eval_point(k2, std::uint8_t{42})),
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dpf::as_share(k3, dpf::eval_point(k3, std::uint8_t{42})));
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```
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Party meshes and socket walks live under [trio.hpp](@ref dpf/net/trio.hpp)
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and the `party/` harnesses. Application-shaped sketches include
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[3-party Duoram](@ref app_duoram) and [three-server PIR](@ref app_pir3).
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**Go deeper:** [guided tour — three evaluators](@ref tour_dpf3),
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[Doerner–Shelat](@ref tour_ds), [evaluating DPFs](@ref evaluation),
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[bibliography](@ref bibliography).
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