112 lines
4.5 KiB
C++
112 lines
4.5 KiB
C++
#pragma once
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#include <cstddef>
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#include <cstdint>
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#include <type_traits>
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#include <bit>
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namespace homcert::bfv {
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constexpr std::size_t VECSIZE = 8192;
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constexpr std::size_t PLAINMOD = 16760833; // 8192*2*1023+1 and prime
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template<std::size_t N, typename = void>
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struct smallest_uint;
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template<std::size_t N>
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struct smallest_uint<N, std::enable_if_t<(N <= UINT8_MAX)>> {
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using type = std::uint8_t;
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};
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template<std::size_t N>
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struct smallest_uint<N, std::enable_if_t<(UINT8_MAX < N && N <= UINT16_MAX)>> {
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using type = std::uint16_t;
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};
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template<std::size_t N>
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struct smallest_uint<N, std::enable_if_t<(UINT16_MAX < N && N <= UINT32_MAX)>> {
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using type = std::uint32_t;
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};
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template<std::size_t N>
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struct smallest_uint<N, std::enable_if_t<(UINT32_MAX < N)>> {
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using type = std::uint64_t;
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};
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struct plaintext {
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using coefficient = typename smallest_uint<PLAINMOD>::type;
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std::array<coefficient, VECSIZE> coefficients;
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// Arithmetic...
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};
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using ciphertext = int;
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// TODO -> Exception with enum that differentiates reason (e.g. CONTEXT_NO_PRIVATE)
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// Inheriting from context class allows pluggability of implementations (e.g. SEAL vs. GPU)
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struct context {
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static constexpr int PUBLIC_COMPONENT = 1;
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static constexpr int PRIVATE_COMPONENT = 2;
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virtual ~context();
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virtual void new_components(int components) = 0; // context default constructs empty
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virtual void has_components(int components) const = 0;
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virtual void clone_components(int components, std::shared_ptr<context>& ptr) const = 0;
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// virtual void dump_components(int components, void* buf, std::size_t& n) const = 0;
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// virtual void load_components(int components, const void* buf, std::size_t n) = 0;
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virtual void allocate(ciphertext& ct) = 0;
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virtual void free(ciphertext ct) = 0;
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virtual void serialize(ciphertext ct, void* buf, std::size_t& n) const = 0;
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virtual void deserialize(ciphertext ct, const void* buf, std::size_t n) const = 0;
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virtual void encrypt(const plaintext& pt, ciphertext ct) const = 0;
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virtual void decrypt(ciphertext ct, plaintext& pt) const = 0; // private
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virtual void add_cipher_plain(ciphertext a, const plaintext& b, ciphertext res) const = 0;
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virtual void add_cipher_cipher(ciphertext a, ciphertext b, ciphertext res) const = 0;
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virtual void sub_cipher_plain(ciphertext a, const plaintext& b, ciphertext res) const = 0;
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virtual void sub_cipher_cipher(ciphertext a, ciphertext b, ciphertext res) const = 0;
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virtual void mul_cipher_plain(ciphertext a, const plaintext& b, ciphertext res) const = 0;
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virtual void mul_cipher_cipher(ciphertext a, ciphertext b, ciphertext res) const = 0;
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virtual void rot_cipher_rows(ciphertext ct, int r, ciphertext res) const = 0;
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virtual void swap_cipher_rows(ciphertext ct, ciphertext res) const = 0;
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virtual void noise_budget(ciphertext ct, std::size_t& budget) const = 0; // private
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};
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/*
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NOTE -> Implementations may defer operations or not wait for them to finish
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For example, GPU implementations may dispatch multiplications when they arive
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Additionally, a graph of running operations is maintained to handle data dependencies
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Only when data is required to actually be present (e.g. decrypt), does the implementation wait
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*/
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/*
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activate_context(std::shared_ptr<bfv::context> ctx) -> thread local pointer is set
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Raw ciphertext and plaintext classes always have the full 8192 coefficients (defined in context as static constexpr)
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bfv::vector<...>
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-> can be plaintext or ciphertext
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-> can be base (owns plain-/ciphertext) or component (view to part of base)
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-> can be local or remote
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-> can be a single vector or multiple vectors/components (variadic)
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-> arithmetic with component masks it out
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-> arithmetic with base does operation on all components
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-> tracks multiplicative depth
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-> warning/error if multiplicative depth exceeds limit
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-> use bootstrap member function to handle the warnings/errors
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-> callbacks to reach peer in context
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-> bootstrap_client (unchecked, just raw bootstrap, checks happen at an upper layer using other callbacks)
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-> bootstrap_server_await (waits for client to make request)
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-> bootstrap_server_serve (called immediately after request received with value to be returned)
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-> automatically does secure reveal when cipher is transformed to plain
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-> queues operations until used (cast to plaintext, communication with peer)
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Programs are defined TWICE
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-> local stuff is executed
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-> remote stuff is hosted (e.g. bootstrapping server)
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-> defined once from each side (differ e.g. in the plaintext inputs etc.)
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-> program base class may be used to handle context setting
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*/
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}
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