wip on BR + added enc/dec for LWE

core/src/blind_rotation/ccgi.rs

@@ -0,0 +1,139 @@
+use std::time::Instant;
+
+use backend::{MatZnxDftOps, MatZnxDftScratch, Module, ScalarZnxDftOps, Scratch, VecZnxDftOps, VecZnxOps, ZnxView, ZnxViewMut, ZnxZero, FFT64};
+use itertools::izip;
+
+use crate::{
+    GGSWCiphertext, GLWECiphertext, GLWECiphertextToMut, GLWECiphertextToRef, GLWEPlaintext, Infos, LWECiphertext,
+    ScratchCore, blind_rotation::key::BlindRotationKeyCGGI, lwe::ciphertext::LWECiphertextToRef,
+};
+
+pub fn cggi_blind_rotate_scratch_space(
+    module: &Module<FFT64>,
+    basek: usize,
+    k_lut: usize,
+    k_brk: usize,
+    rows: usize,
+    rank: usize,
+) -> usize {
+    let size = k_brk.div_ceil(basek);
+    GGSWCiphertext::<Vec<u8>, FFT64>::bytes_of(module, basek, k_brk, rows, 1, rank)
+        + (module.mat_znx_dft_mul_x_pow_minus_one_scratch_space(size, rank + 1)
+            | GLWECiphertext::external_product_inplace_scratch_space(module, basek, k_lut, k_brk, 1, rank))
+}
+
+pub fn cggi_blind_rotate<DataRes, DataIn, DataLUT>(
+    module: &Module<FFT64>,
+    res: &mut GLWECiphertext<DataRes>,
+    lwe: &LWECiphertext<DataIn>,
+    lut: &GLWEPlaintext<DataLUT>,
+    brk: &BlindRotationKeyCGGI<FFT64>,
+    scratch: &mut Scratch,
+) where
+    DataRes: AsRef<[u8]> + AsMut<[u8]>,
+    DataIn: AsRef<[u8]>,
+    DataLUT: AsRef<[u8]>,
+{
+
+    println!("{}", lwe.n());
+
+    let mut lwe_2n: Vec<i64> = vec![0i64; lwe.n() + 1]; // TODO: from scratch space
+    let mut out_mut: GLWECiphertext<&mut [u8]> = res.to_mut();
+    let lwe_ref: LWECiphertext<&[u8]> = lwe.to_ref();
+    let lut_ref: GLWECiphertext<&[u8]> = lut.to_ref();
+
+    let cols = out_mut.rank()+1;
+
+    mod_switch_2n(module, &mut lwe_2n, &lwe_ref);
+
+    let a: &[i64] = &lwe_2n[1..];
+    let b: i64 = lwe_2n[0];
+
+    out_mut.data.zero();
+
+    // Initialize out to X^{b} * LUT(X)
+    module.vec_znx_rotate(b, &mut out_mut.data, 0, &lut_ref.data, 0);
+
+    let block_size: usize = brk.block_size();
+
+    // ACC + [sum DFT(X^ai -1) * (DFT(ACC) x BRKi)]
+
+    let (mut acc_dft, scratch1) = scratch.tmp_glwe_fourier(module, brk.basek(), out_mut.k(), out_mut.rank());
+    let (mut acc_add_dft, scratch2) = scratch1.tmp_glwe_fourier(module, brk.basek(), out_mut.k(), out_mut.rank());
+    let (mut vmp_res, scratch3) = scratch2.tmp_vec_znx_dft(module, acc_dft.rank()+1, acc_dft.size());
+    let (mut xai_minus_one, scratch4) = scratch3.tmp_scalar_znx(module, 1);
+    let (mut xai_minus_one_dft, scratch5) = scratch4.tmp_scalar_znx_dft(module, 1);
+
+    let start: Instant = Instant::now();
+    izip!(
+        a.chunks_exact(block_size),
+        brk.data.chunks_exact(block_size)
+    )
+    .for_each(|(ai, ski)| {
+
+        out_mut.dft(module, &mut acc_dft);
+        acc_add_dft.data.zero();
+        
+        izip!(ai.iter(), ski.iter())
+            .enumerate()
+            .for_each(|(i, (aii, skii))| {
+
+                // vmp_res = DFT(acc) * BRK[i]
+                module.vmp_apply(&mut vmp_res, &acc_dft.data, &skii.data, scratch5);
+
+                // DFT(X^ai -1)
+                xai_minus_one.zero();
+                xai_minus_one.at_mut(0, 0)[0] = 1;
+                module.vec_znx_rotate_inplace(*aii, &mut xai_minus_one, 0);
+                xai_minus_one.at_mut(0, 0)[0] -= 1;
+                module.svp_prepare(&mut xai_minus_one_dft, 0, &xai_minus_one, 0);
+
+                // DFT(X^ai -1) * (DFT(acc) * BRK[i])
+                (0..cols).for_each(|i|{
+                    module.svp_apply_inplace(&mut vmp_res, i, &xai_minus_one_dft, 0);
+                    module.vec_znx_dft_add_inplace(&mut acc_add_dft.data, i, &vmp_res, i);
+                });
+            
+            });
+        
+        acc_add_dft.idft(module, &mut out_mut, scratch5);
+    });
+    let duration: std::time::Duration = start.elapsed();
+    println!("external products: {} us", duration.as_micros());
+}
+
+fn mod_switch_2n(module: &Module<FFT64>, res: &mut [i64], lwe: &LWECiphertext<&[u8]>) {
+    let basek: usize = lwe.basek();
+
+    let log2n: usize = module.log_n() + 1;
+
+    res.copy_from_slice(&lwe.data.at(0, 0));
+
+    if basek > log2n {
+        let diff: usize = basek - log2n;
+        res.iter_mut().for_each(|x| {
+            *x = div_signed_by_pow2(x, diff);
+        })
+    } else {
+        let rem: usize = basek - (log2n % basek);
+        let size: usize = log2n.div_ceil(basek);
+        (1..size).for_each(|i| {
+            if i == size - 1 && rem != basek {
+                let k_rem: usize = basek - rem;
+                izip!(lwe.data.at(0, i).iter(), res.iter_mut()).for_each(|(x, y)| {
+                    *y = (*y << k_rem) + (x >> rem);
+                });
+            } else {
+                izip!(lwe.data.at(0, i).iter(), res.iter_mut()).for_each(|(x, y)| {
+                    *y = (*y << basek) + x;
+                });
+            }
+        })
+    }
+}
+
+#[inline(always)]
+fn div_signed_by_pow2(x: &i64, k: usize) -> i64 {
+    let bias: i64 = (1 << k) - 1;
+    (x + ((x >> 63) & bias)) >> k
+}