mirror of
https://github.com/arnaucube/poulpy.git
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c7219c35e9
* Move br + cbt to schemes/tfhe * refactor blind rotation * refactor circuit bootstrapping * renamed exec -> prepared
296 lines
12 KiB
Rust
296 lines
12 KiB
Rust
use backend::hal::{
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api::{
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ScratchAvailable, TakeVecZnx, TakeVecZnxBig, TakeVecZnxDft, VecZnxBigAllocBytes, VecZnxCopy, VecZnxDftAddInplace,
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VecZnxDftCopy, VecZnxDftToVecZnxBigTmpA, VecZnxNormalizeTmpBytes, ZnxInfos,
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},
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layouts::{Backend, DataMut, DataRef, Module, Scratch, VecZnx, VmpPMat},
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};
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use crate::{
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layouts::{
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GGLWECiphertext, GGSWCiphertext, GLWECiphertext, Infos,
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prepared::{GGLWESwitchingKeyPrepared, GGLWETensorKeyPrepared},
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},
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operations::GLWEOperations,
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trait_families::{GGSWKeySwitchFamily, GLWEKeyswitchFamily},
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};
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impl GGSWCiphertext<Vec<u8>> {
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pub(crate) fn expand_row_scratch_space<B: Backend>(
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module: &Module<B>,
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n: usize,
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basek: usize,
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self_k: usize,
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k_tsk: usize,
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digits: usize,
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rank: usize,
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) -> usize
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where
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Module<B>: GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
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{
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let tsk_size: usize = k_tsk.div_ceil(basek);
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let self_size_out: usize = self_k.div_ceil(basek);
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let self_size_in: usize = self_size_out.div_ceil(digits);
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let tmp_dft_i: usize = module.vec_znx_dft_alloc_bytes(n, rank + 1, tsk_size);
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let tmp_a: usize = module.vec_znx_dft_alloc_bytes(n, 1, self_size_in);
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let vmp: usize = module.vmp_apply_tmp_bytes(
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n,
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self_size_out,
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self_size_in,
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self_size_in,
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rank,
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rank,
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tsk_size,
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);
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let tmp_idft: usize = module.vec_znx_big_alloc_bytes(n, 1, tsk_size);
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let norm: usize = module.vec_znx_normalize_tmp_bytes(n);
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tmp_dft_i + ((tmp_a + vmp) | (tmp_idft + norm))
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}
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pub fn keyswitch_scratch_space<B: Backend>(
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module: &Module<B>,
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n: usize,
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basek: usize,
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k_out: usize,
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k_in: usize,
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k_ksk: usize,
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digits_ksk: usize,
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k_tsk: usize,
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digits_tsk: usize,
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rank: usize,
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) -> usize
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where
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Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
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{
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let out_size: usize = k_out.div_ceil(basek);
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let res_znx: usize = VecZnx::alloc_bytes(n, rank + 1, out_size);
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let ci_dft: usize = module.vec_znx_dft_alloc_bytes(n, rank + 1, out_size);
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let ks: usize = GLWECiphertext::keyswitch_scratch_space(module, n, basek, k_out, k_in, k_ksk, digits_ksk, rank, rank);
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let expand_rows: usize = GGSWCiphertext::expand_row_scratch_space(module, n, basek, k_out, k_tsk, digits_tsk, rank);
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let res_dft: usize = module.vec_znx_dft_alloc_bytes(n, rank + 1, out_size);
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res_znx + ci_dft + (ks | expand_rows | res_dft)
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}
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pub fn keyswitch_inplace_scratch_space<B: Backend>(
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module: &Module<B>,
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n: usize,
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basek: usize,
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k_out: usize,
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k_ksk: usize,
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digits_ksk: usize,
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k_tsk: usize,
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digits_tsk: usize,
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rank: usize,
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) -> usize
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where
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Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
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{
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GGSWCiphertext::keyswitch_scratch_space(
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module, n, basek, k_out, k_out, k_ksk, digits_ksk, k_tsk, digits_tsk, rank,
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)
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}
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}
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impl<DataSelf: DataMut> GGSWCiphertext<DataSelf> {
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pub fn from_gglwe<DataA, DataTsk, B: Backend>(
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&mut self,
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module: &Module<B>,
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a: &GGLWECiphertext<DataA>,
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tsk: &GGLWETensorKeyPrepared<DataTsk, B>,
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scratch: &mut Scratch<B>,
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) where
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DataA: DataRef,
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DataTsk: DataRef,
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Module<B>: GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes + VecZnxCopy,
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Scratch<B>: TakeVecZnxDft<B> + TakeVecZnxBig<B> + ScratchAvailable + TakeVecZnx,
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{
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#[cfg(debug_assertions)]
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{
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assert_eq!(self.rank(), a.rank());
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assert_eq!(self.rows(), a.rows());
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assert_eq!(self.n(), module.n());
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assert_eq!(a.n(), module.n());
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assert_eq!(tsk.n(), module.n());
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}
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(0..self.rows()).for_each(|row_i| {
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self.at_mut(row_i, 0).copy(module, &a.at(row_i, 0));
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});
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self.expand_row(module, tsk, scratch);
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}
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pub fn keyswitch<DataLhs: DataRef, DataKsk: DataRef, DataTsk: DataRef, B: Backend>(
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&mut self,
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module: &Module<B>,
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lhs: &GGSWCiphertext<DataLhs>,
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ksk: &GGLWESwitchingKeyPrepared<DataKsk, B>,
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tsk: &GGLWETensorKeyPrepared<DataTsk, B>,
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scratch: &mut Scratch<B>,
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) where
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Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
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Scratch<B>: TakeVecZnxDft<B> + TakeVecZnxBig<B> + ScratchAvailable,
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{
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self.keyswitch_internal(module, lhs, ksk, scratch);
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self.expand_row(module, tsk, scratch);
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}
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pub fn keyswitch_inplace<DataKsk: DataRef, DataTsk: DataRef, B: Backend>(
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&mut self,
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module: &Module<B>,
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ksk: &GGLWESwitchingKeyPrepared<DataKsk, B>,
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tsk: &GGLWETensorKeyPrepared<DataTsk, B>,
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scratch: &mut Scratch<B>,
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) where
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Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
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Scratch<B>: TakeVecZnxDft<B> + TakeVecZnxBig<B> + ScratchAvailable,
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{
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unsafe {
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let self_ptr: *mut GGSWCiphertext<DataSelf> = self as *mut GGSWCiphertext<DataSelf>;
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self.keyswitch(module, &*self_ptr, ksk, tsk, scratch);
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}
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}
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pub fn expand_row<DataTsk: DataRef, B: Backend>(
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&mut self,
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module: &Module<B>,
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tsk: &GGLWETensorKeyPrepared<DataTsk, B>,
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scratch: &mut Scratch<B>,
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) where
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Module<B>: GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
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Scratch<B>: TakeVecZnxDft<B> + TakeVecZnxBig<B> + ScratchAvailable,
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{
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assert!(
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scratch.available()
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>= GGSWCiphertext::expand_row_scratch_space(
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module,
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self.n(),
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self.basek(),
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self.k(),
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tsk.k(),
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tsk.digits(),
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tsk.rank()
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)
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);
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let n: usize = self.n();
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let rank: usize = self.rank();
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let cols: usize = rank + 1;
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// Keyswitch the j-th row of the col 0
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(0..self.rows()).for_each(|row_i| {
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// Pre-compute DFT of (a0, a1, a2)
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let (mut ci_dft, scratch1) = scratch.take_vec_znx_dft(n, cols, self.size());
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(0..cols).for_each(|i| {
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module.vec_znx_dft_from_vec_znx(1, 0, &mut ci_dft, i, &self.at(row_i, 0).data, i);
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});
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(1..cols).for_each(|col_j| {
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// Example for rank 3:
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//
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// Note: M is a vector (m, Bm, B^2m, B^3m, ...), so each column is
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// actually composed of that many rows and we focus on a specific row here
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// implicitely given ci_dft.
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//
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// # Input
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//
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// col 0: (-(a0s0 + a1s1 + a2s2) + M[i], a0 , a1 , a2 )
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// col 1: (0, 0, 0, 0)
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// col 2: (0, 0, 0, 0)
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// col 3: (0, 0, 0, 0)
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//
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// # Output
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//
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// col 0: (-(a0s0 + a1s1 + a2s2) + M[i], a0 , a1 , a2 )
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// col 1: (-(b0s0 + b1s1 + b2s2) , b0 + M[i], b1 , b2 )
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// col 2: (-(c0s0 + c1s1 + c2s2) , c0 , c1 + M[i], c2 )
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// col 3: (-(d0s0 + d1s1 + d2s2) , d0 , d1 , d2 + M[i])
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let digits: usize = tsk.digits();
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let (mut tmp_dft_i, scratch2) = scratch1.take_vec_znx_dft(n, cols, tsk.size());
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let (mut tmp_a, scratch3) = scratch2.take_vec_znx_dft(n, 1, ci_dft.size().div_ceil(digits));
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{
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// Performs a key-switch for each combination of s[i]*s[j], i.e. for a0, a1, a2
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//
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// # Example for col=1
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//
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// a0 * (-(f0s0 + f1s1 + f1s2) + s0^2, f0, f1, f2) = (-(a0f0s0 + a0f1s1 + a0f1s2) + a0s0^2, a0f0, a0f1, a0f2)
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// +
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// a1 * (-(g0s0 + g1s1 + g1s2) + s0s1, g0, g1, g2) = (-(a1g0s0 + a1g1s1 + a1g1s2) + a1s0s1, a1g0, a1g1, a1g2)
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// +
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// a2 * (-(h0s0 + h1s1 + h1s2) + s0s2, h0, h1, h2) = (-(a2h0s0 + a2h1s1 + a2h1s2) + a2s0s2, a2h0, a2h1, a2h2)
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// =
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// (-(x0s0 + x1s1 + x2s2) + s0(a0s0 + a1s1 + a2s2), x0, x1, x2)
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(1..cols).for_each(|col_i| {
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let pmat: &VmpPMat<DataTsk, B> = &tsk.at(col_i - 1, col_j - 1).key.data; // Selects Enc(s[i]s[j])
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// Extracts a[i] and multipies with Enc(s[i]s[j])
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(0..digits).for_each(|di| {
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tmp_a.set_size((ci_dft.size() + di) / digits);
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// Small optimization for digits > 2
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// VMP produce some error e, and since we aggregate vmp * 2^{di * B}, then
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// we also aggregate ei * 2^{di * B}, with the largest error being ei * 2^{(digits-1) * B}.
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// As such we can ignore the last digits-2 limbs safely of the sum of vmp products.
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// It is possible to further ignore the last digits-1 limbs, but this introduce
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// ~0.5 to 1 bit of additional noise, and thus not chosen here to ensure that the same
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// noise is kept with respect to the ideal functionality.
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tmp_dft_i.set_size(tsk.size() - ((digits - di) as isize - 2).max(0) as usize);
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module.vec_znx_dft_copy(digits, digits - 1 - di, &mut tmp_a, 0, &ci_dft, col_i);
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if di == 0 && col_i == 1 {
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module.vmp_apply(&mut tmp_dft_i, &tmp_a, pmat, scratch3);
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} else {
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module.vmp_apply_add(&mut tmp_dft_i, &tmp_a, pmat, di, scratch3);
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}
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});
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});
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}
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// Adds -(sum a[i] * s[i]) + m) on the i-th column of tmp_idft_i
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//
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// (-(x0s0 + x1s1 + x2s2) + a0s0s0 + a1s0s1 + a2s0s2, x0, x1, x2)
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// +
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// (0, -(a0s0 + a1s1 + a2s2) + M[i], 0, 0)
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// =
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// (-(x0s0 + x1s1 + x2s2) + s0(a0s0 + a1s1 + a2s2), x0 -(a0s0 + a1s1 + a2s2) + M[i], x1, x2)
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// =
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// (-(x0s0 + x1s1 + x2s2), x0 + M[i], x1, x2)
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module.vec_znx_dft_add_inplace(&mut tmp_dft_i, col_j, &ci_dft, 0);
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let (mut tmp_idft, scratch3) = scratch2.take_vec_znx_big(n, 1, tsk.size());
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(0..cols).for_each(|i| {
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module.vec_znx_dft_to_vec_znx_big_tmp_a(&mut tmp_idft, 0, &mut tmp_dft_i, i);
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module.vec_znx_big_normalize(
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self.basek(),
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&mut self.at_mut(row_i, col_j).data,
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i,
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&tmp_idft,
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0,
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scratch3,
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);
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});
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})
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})
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}
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fn keyswitch_internal<DataLhs: DataRef, DataKsk: DataRef, B: Backend>(
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&mut self,
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module: &Module<B>,
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lhs: &GGSWCiphertext<DataLhs>,
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ksk: &GGLWESwitchingKeyPrepared<DataKsk, B>,
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scratch: &mut Scratch<B>,
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) where
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Module<B>: GLWEKeyswitchFamily<B> + GGSWKeySwitchFamily<B> + VecZnxNormalizeTmpBytes,
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Scratch<B>: TakeVecZnxDft<B> + TakeVecZnxBig<B> + ScratchAvailable,
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{
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// Keyswitch the j-th row of the col 0
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(0..lhs.rows()).for_each(|row_i| {
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// Key-switch column 0, i.e.
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// col 0: (-(a0s0 + a1s1 + a2s2) + M[i], a0, a1, a2) -> (-(a0s0' + a1s1' + a2s2') + M[i], a0, a1, a2)
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self.at_mut(row_i, 0)
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.keyswitch(module, &lhs.at(row_i, 0), ksk, scratch);
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})
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}
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}
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